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Time Travel in yourgame?


Lord of the Hidden Layer
Your mission, should you choose to accept it …
At the beginning of World War One, the German battlecruiser Goeben must be prevented from reaching Constantinople.

Headache Part One: the easiest way to achieve that is for Goeben to run into a British or French cruiser squadron and get into a fight. Which means you have to 'persuade' several admirals to do something they want to do anyways. BUT how do you control the fall of shot so that Goeben takes damage and must run for the nearest neutral (read: Italian*) port, likely to get interned / scuttled?

IRL, Goeben did make it to Constantinople. The ramifications were disastrous for the Ottoman Empire, Russian Empire, and the Balkan nations. A generation later Germany too was drawn into the conflagration ('We were winning WW1 but were backstabbed'). And there is a Palestine to argue over to this day because the ex-Ottoman province of Syria was split up.

Headache Part 2: What is so bad that happens in the Alternate History that 'let Goeben get through' looks like a BETTER alternative?

* less likely: or Greek or Spanish

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So, basically, if you dare to travel in time, your world will suck forever.

As much as I am predisposed to tragedy and fatalism, I don't think i would make a time travel RPG that fatalistic and tragic. It would kill a lot of the joy of a game.

There will always be additional challenges and complications. If in a regular game the party defeats the crime boss or orc chief, then they have to deal with a worse crime boss or a necromancer as the party levels up and the stakes escalate. And the specifics of the next challenges are something they usually cannot see as they deal with the first crime boss or orc tribe. The same is true of saving Lincoln or Kennedy, assuming saving the presidents was not the final arc of the campaign.

If they do change history, they will remember the original time line, not the one they created. Learning the details of the new time line can be fodder for a new adventure.


In general I avoid time travelling, as I'm not very confident I can manage everything in style, but there are a few super-classic modules, like the DA series and Where Chaos Reigns that are a great support for running a long adventure with timetravelling in it.


Mod Squad
Staff member
Headache Part One: the easiest way to achieve that is for Goeben to run into a British or French cruiser squadron and get into a fight.

That's the most obvious. The *easiest* would probably be sabotage. Say, to go back well before this trip, and sabotage the drive shaft or some other part, so that the ship needs to be in dry dock or falls dead in the water on its way. Or, in the present you find a copy of the ship's orders, and you forge new ones, that send it elsewhere. Or... one of any number of things that are well within the espionage bailiwick.

When in doubt, maneuvering hundreds or thousands of people (the crews of the other ships) to do your bidding is probably not the *easiest* way to do a thing.

Thomas Bowman

First Post
So, basically, if you dare to travel in time, your world will suck forever. Time travel is a trap, allowed by the GM, but which no player would ever want to do - and players cannot know the trap, because the information gets lost in timeline revisions and the attendant memory changes. Similarly, they cannot leave the trap, because the information on what they changed gets lost, so they cannot undo their own changes.

GM: "Here's a corridor. I won't tell you what's down it."
Players: "Okay, let us investigate!"
GM: "Rocks fall, everyone dies! I guess that was a bad corridor to go down."

It may seem logical, but unless your players like frustration and misery, it seems like a bad design choice for a game.

I would say that changes in the timeline do not propagate backwards in time to catch up with the time travellers, so they would know what changes the wrought and what mistakes they made. This is sort of what happens in the show Timeless. If someone goes back in time for a specific reason, such as to make a change which undoes the reason for making the trip in the first place, then that change cannot be made, something goes wrong which prevents that change from occurring, maybe another unsatisfactory result occurs thus necessitating the journey back in time in the first place Now what would happen if the time travellers were successful, the change in the timeline does not propagate backwards in time to the time travellers making the change.

In the new timeline they have created, they have not gone back in time, as they have no reason to. So when the time travellers return to the present, they find duplicates of themselves and their time machine, and those duplicates wonder what the originals are doing there! Even worse, is they return to a completely different present with no one alive that they recognize, and nobody recognizes them either, they may have saved Kennedy, but the present they return to is completely unfamiliar, and they are strangers among them, but that would create a lot of work for the GM to fabricate a completely new timeline that begins where the PCs have made the change, where different people are born for example.

I think most GMs would prefer a timeline that "heals" somewhat and returns to something resembling the original, that means the timeline resists change, and the PCs would find their own duplicates in the new timeline they created, if they create a change that undermines the reason for making that particular trip back in time in the first place.

I would say that we not let such a change occur and so the PCs and their time machine is not duplicated, but other changes could occur during their trip that do not undermine their reason for making the trip in the first place. The PCs return to the present in the new timeline with memories of the original timeline. As for as the people in the new timeline are concerned, the people who returned from their mission are not quite the same people that they sent on their mission, and while their mission to make that specific change they intended to make was a failure, other changes to the timeline were inadvertently made during that trip. But to the inhabitants of the new timeline, as far as they are concerned, the timeline was always this way, it is only the time travellers they sent into the past who are different.

That is how the show Timeless deals with time travel.


Ravenous Bugblatter Beast of Traal
I've been involved in time traveling as both player and DM several times, but never in a D&D-type game. Well, not entirely true, there was an adventure in the far past, but it was very strictly limited in scope.

Superheroes has been the most common time-travel genre, up to the point where one player had a character who was a time agent who worked to keep the timeline "correct". (In a game where everyone had a stable of characters.)

It's been in others. Was in a GURPS game where we all played ourselves (back in college), and we inadvertently got caught up in time travel. We ended up stopping Lee Harvey Oswald only to be found by other time travelers and told we had created a nightmare world and had to put it back, with the code-vs-killing Me being the only one with firearm experience and having to take the shot, which was wonderfully dramatic in messing up my character's psyche.

Another point I've done in planar travel with different velocities of time, so when they got back from the Fey court (prior to Feywilds being a thing, but the same base inspiration) they found that over a well year had passed in the real world and things had moved on.

Thomas Bowman

First Post
I think one reason you create a nightmare world is that whatever changes you make to the timeline, in that new timeline, your characters need a reason to go back in time and change the timeline in order to avoid duplicating yourselves when you return to the present. In Timeless for instance Wyatt Logan tried to go back in time to prevent his wife's murder, so he went back to the 1980s to prevent the murder's mother and father from getting together and thus prevent the murderer of his wife from ever being born. Turns out it didn't work, his wife was still murdered. Later on Rittenhouse managed to bring back Wyatt's wife and turn her into a sleeper agent. the reason it worked then was because unlike Wyatt Logan, they had multiple reasons for going back into time to that period.

1) To resurrect Wyatt's wife
2) To turn her into a sleeper agent
3) So save her brother from Leukemia

Wyatt's wife Jessica started out murdered, when Rittenhouse "unmurdered" her, they still had a second reason to go back in time in the new timeline, that would be to turn her into a sleeper agent, and they used the leverage of saving her brother to get her to agree, and then they instructed her to marry Wyatt and keep the secret till the appointed time so the timeline would not change to eliminate their reason for going back in time and doing this to her in the first place. That is how you change the timeline without eliminating the reason for going back in time.

Now how would you apply this logic to "unmurdering" John F. Kennedy. You would have to create a second reason for going back in time besides saving Kennedy's life. If the sole reason for going back in time is to save the President, then the mission is going to fail. There was an episode in Timeless, where JFK was brought to the present, and the time crew lost track of him for a time. In the process of getting lost, John F. Kennedy encountered a group of teenagers. For some reason Rittenhouse wanted to murder JFK when he was much younger, in the 1930s for example.

What could be the second reason for going back in time? Maybe to warn JFK about an impending World War that was going to kill his brother Joseph P Kennedy Jr. I had myself thinking whether JFK could have prevented World War II if he was sent back to the 1930s with foreknowledge of the future. JFK knows that World War II was going to kill his brother, thus he would have motivation to try and prevent World War II by perhaps killing Hitler. So in the new timeline where JFK doesn't get assassinated, maybe time agents would still go back in time to warn Kennedy that his brother was going to be killed in World War II. if you send time agents back in time to do two things at once and only one of them fails, you still have reason to go back in time, even if you are successful at one thing but not the other.

So in another timeline, where Kennedy serves out his full two terms as president, the time agents go back to the present and are told that their mission failed because Joseph P. Kennedy Jr still died in World War II.

In the case of Wyatt's wife, one of the objectives was to turn her into a sleeper agent, and as a sleeper agent, she was not activated, until after the moment Rittenhouse departed for the past to change the timeline. Since Jessica was instructed not to reveal herself as a sleeper agent before the mission to change the timeline was sent, then that mission was an apparent failure, presumably there was a timeline where she was not murdered, but still Rittenhouse had reason to go back in time to turn her into a sleeper agent, and since she was undercover, the fact that she was a sleeper agent had no effect on the timeline until she chose to reveal herself to Wyatt, otherwise she acted just as she would have were she not a sleeper agent. The apparent failure of her to be a sleeper agent still motivated Rittenhouse to go back in time and try to turn her into one.

That is how you change a timeline without violating these rules. you have to be a little clever and have multiple reasons for going back in time so that one can succeed.
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So one of the angles I’m going with in my campaign is predetermination versus free will. Are events fixed? Can you change the past, or the future?

I’ve not really decided the actual answer. I want to see what my players come up with and how events come to pass. I’ve been sure to present both ideas, primarily through two characters. One is an oracle of sorts who sees possible futures and tries to bring about the most desirable. She thinks the future is not set in stone. The second is the mad time traveller; he’s convinced that everything is fixed and that nothing can be changed. If you go to the past to prevent someone’s death, you’ve obviously already failed because succeeding would create a paradox.

So the PCs have learned that they need another group of heroes if they’re going to succeed....but this is a group of heroes that has been gone for 5 years, supposedly killed by a group of villains. So they’re suppsedly dead, but no one knows exactly what happened to them except the bad guys.

So one of my players is convinced that the crazy time traveller is right and that everythibg’s set. So if the heroes are dead, then they’re dead. But since the PCs haven’t confirmed that the heroes are dead, then who says that’s true? What’s to stop the PCs from travelling back in time, helping the heroes beat the bad guys or at the very least escape from them...and then return to the present with the heroes in tow?

This would seem to be possible whether time is mutable or not...I was pretty impressed with the idea, and I’m eager to see how they try to pull this off.


First Post
By traveling back in time you create a new timeline. There's never any paradox because your old timeline remains completely unaffected. Or am I missing something?


Mod Squad
Staff member
By traveling back in time you create a new timeline. There's never any paradox because your old timeline remains completely unaffected. Or am I missing something?

To be clear - nobody has ever done this, so what happens when you do it is fiction, and we get to choose.

For example, Mr. Bowman, above, says that if you travel in time, you *cannot* end in a state that removes the reason you traveled back in time. That's *his* restriction. He feels that's the appropriate logic. But that's a choice for metaphysics in his world. It isn't the most common choice - usually, you see a person travels in time, changes the past, and comes forward again. Kennedy lived (thanks to them), so they have no reason to go back to the Grassy Knoll, but they do not remember the new history, and come back not knowing, for example, that Madonna is now President of the USA.

While Mr. Bowman refers to Timeless, the show doesn't rigorously use his metaphysic in general. This may not be obvious at first, because the protagonists are reactive - they almost always travel in reaction ot the bad guys travelling - so long as the bad guys have a reason to travel, so do they. But, let us look more closely at the episode mentioned....

In backstory, before the series begins, Wyatt's wife Jessica is murdered. Wyatt is told a man who is in jail for two other murders did it. So, Wyatt goes back in time to make sure this serial killer is never born. He *succeeds*, by killing the murderer's father, the murderer is never born. When he returns, the two other women are alive, but Wyatt's wife is still dead.

Here's the thing - in this, Wyatt *does* remove the reason for him to go back in time. He went back to remove a serial killer from history. He did so. That serial killer does not exist. He cannot go back in time to stop the birth of a man who never existed! His wife is still dead, but that fact is not a reason for him to take that time trip! This episode violates Mr. Bowman's metaphysics.

Timelsss has been smart, in that it has not laid out all the rules of time travel for us to see. The only rule they have is that you cannot travel to a time in which you already exist. In the final episode of the second season, that rule is broken, as future versions of a couple of the characters show up in our present in a heavily modified time machine.

If you run time travel, you get to choose how it works.
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Thomas Bowman

First Post
True enough, the Gm should never reveal the precise rules of time travel to the players, there are two extremes which don't really work in a role playing game.
1) History can never be changed
2) Whenever history is changed you always create an alternate timeline, even if you do the slightest thing, such as simply travel to the past, the butterfly effect will lead to different historic outcomes when you return to the present.

If you can never change history, why bother going into the past, one has to be careful never to get in a situation where your presence may potentially be recorded in history books, because then something happens to you to make sure that it isn't, since you were not found in the history books before you made the trip, and what was written in the history books cannot change as a result of your traveling into the past, this also goes as far as leaving no trace of your existence. You can perhaps go back and hunt dinosaurs, but if you try to go to the Moon and leave footprints on the site of the Apollo 11 landing, then the timeline will stop you from doing that, you will never get there, you will be hit by a meteor or something like that to prevent you from ever making footprints on the Moon.

if you are always creating an alternate timeline, then you can't return to your present unless you use wormholes, as wormholes can connect two different timelines and two different universes in fact. But if you go back in time and mess around in the past creating another timeline which has no bearing on the present you left, but can return to, then what's the point in making the trip?


Ravenous Bugblatter Beast of Traal
Just remembered a bit of time travel in a less than serious game with rotating DMs. The party was in an inter-dimensional bazaar where anything was for sale, and they needed to be able to time travel (I don't remember why). So they tracked down a lead where to go and are heading there, when across a busy street they see themselves. The other set of them wave and yell out over the traffic "don't forget to get reverse time batteries!".

So they get there to the place, a demo of the device puts them back in time 10 minutes. They purchase a new one in box, are about to walk out when on goes "oh wait, we need batteries". *ka-ching* They get those, walk out and I describe how the clock nearby was earlier then when they went in (because of the demo).

One of the players says "I look around for us" heading there.
"You see you."
"I wave and call out 'Don't forget to get reverse time batteries'."

Ah, I loved my players.


Mod Squad
Staff member
If you can never change history, why bother going into the past

Oh, this is simple - to get information that is relevant to the present. I mean, you can do this with a postcognition spell too, but if you are there, and can interact, but nothing will change, you can probably get more information.

Imagine you are tasked with catching a murderer. Go back in time to the last known murder, watch, and *tada!* you get to see who did it. Come back to the present, and nail their sorry butts to the wall for what they did.

I played in a Pathfinder adventure path, where I was eventually allowed access to the Scepter of Ages, on the strict condition that I only go back one month in order to buy enough time for everyone to recover from their negative levels. That worked out well enough.

Later, I ran a 5E campaign where the BBEG acquired the Scepter of Ages at some point during her infinite wish scheme, and used it to take over the world thirty years ago. When the party woke up, the day after the BBEG had acquired the artifact necessary to put her scheme into action, they realized that the whole world was not as they remembered it. They eventually found their way back to the past, and defeated the BBEG, whereupon she dropped the Scepter as loot. Although I was prepared for them to go anywhere else in history that they might want to visit, they decided to just go back to the beginning of the world in order to stop the Sealed Evil before it was sealed in the first place, thus re-writing all of history for the better.

In my opinion, tabletop RPGs are the best way to explore the concept of time travel, since anything can happen as long as the GM can envision it. Novels and movies are too limited, since you only get to see what the author wants you to see, and video games would require everything to be programmed in advance.

True enough, the Gm should never reveal the precise rules of time travel to the players,

When I ran my Call of Cthulhu campaign, a lot of the plot revolved around the players figuring out how time travel worked in the campaign. First it manifested itself as a series of bizarre and spooky events. But eventually they came to understand the phenomenon, and started testing the rules, which uncovered even more spooky things in the process.


Lord of the Hidden Layer
In backstory, before the series begins, Wyatt's wife Jessica is murdered. Wyatt is told a man who is in jail for two other murders did it. So, Wyatt goes back in time to make sure this serial killer is never born. He *succeeds*, by killing the murderer's father, the murderer is never born. When he returns, the two other women are alive, but Wyatt's wife is still dead.
Now we need several trips back, not a 'time-lock'.
- Stop previous time-tripping self mid-mission; I am pursuing the wrong person.
- Trip to scene of Jessica's death, to find out who really killed her.
- Research that person's backstory
- Stop real killer in some other crime (catch him red-handed would be best) that he committed prior to killing Jessica.
- NOW I am ready to go back to Timeline Prime and reunite with (now-living) Jessica.

Thomas Bowman

First Post
There is the rule that you can't go back to a time when you are already alive, but it turns out that rule was only a suggestion anyway. If you wait long enough, you can send a kid back in a time machine who wasn't born yet to gather information.

So I had an interesting idea come to me for my 5E campaign that has time travel shenanigans.

The party Fighter recently had a final showdown with his one time mentor, an aged mercenary who’s sided with the villains because he thinks they’re bound to win. So the Fighter killed the Mercenary...and I had the Merc’s last words be “Now we’re even”.

The idea is that the Merc is at a past event where the bad guys kill some of the PCs allies. The campaign has been going toward the idea that the PCs will go back in time to save those allies. When they do so, they’ll fight the Mercenary and the other villains in their past.

So if/when that happens....the Mercenary could kill the Fighter. So each of them is the other’s killer. It’s the kind of whacky concept that can only come up when time travel is involved.

The idea popped into my head when the Fighter finished him off, so I threw that dialogue out there....and the player definitely took notice. It’ll be interesting to see how it may play out.

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