I'd like to pose the following scenario. Consider the following as a stream of consciousness from the DM.
"Hmmm ... I designed this encounter to be tough but, geeze, I really over estimated what the PCs are capable of. If only Bob was here tonight to play instead of being out sick. If I don't do something these guys are goners."
You are the DM, what do you do?
Assume that in this scenario that retreat is not an option. The avenue of escape has been cut off, the PCs are on a clock, the PCs are gearing up for a doomed last stand and ignoring the exit, et cetera.
Does your decision change if introducing Bob to a bunch of new characters is implausible? What if a TPK means the campaign is over and unresolved?
I'm curious to know what people think.
Alright, so: presuming that I and/or the system have failed so spectacularly that defeat is assured, but the normal escape clauses (being captured or retreating) are complete non-starters, I see at least three possible solutions. I'll list them from worst to best.
1. Tell the players, "Guys, I have




ed up now, I have given you an unwinnable fight. If you're okay with it, I'm going to take a 15 minute break, and when we come back, we'll be doing this fight over from the beginning--because I screwed up. Bad."
This is the worst option because it kinda abandons even a pretense of maintaining fiction continuity, and the players may not even accept it, at which point the problem remains unsolved. If the players to accept it though (and I'd assume many would, if I am open and clear about the fact that this is *my* screwup), this has the benefit of actually fixing the root of the problem: *my* mistake. It doesn't punish the players, and if they treat the "first" fight as non-existent (or perhaps fodder for some other story, e.g. an alt-timeline failure, akin to the "Grima wins" timeline from
Fire Emblem: Awakening) it avoids any concern of "fudging"--or, at least, I don't see this as being the same as "fudging." Re-writing an entire combat, with the explicit permission of the players, is rather a different thing than ignoring actual rolls (in secret, in the open, or pseudo-secret, e.g. "I might ignore dice at any time").
2. Call for a quick (~15 minute) break, during which you attempt to figure out how to extrapolate from the already-established fiction so that you can improve the party's chances of success and/or weaken the bad guys. Potentially, confer with each of the players individually and ask them what they think could go well or poorly. When the group reconvenes, apply these ideas to the fight (whether in progress or about to start). For example: perhaps the fight venue is dangerously unstable, like an ancient ruin or a volcanic cavern. The magical and physical energies released during the combat could easily cause the place to go from unstable to actively unsafe: encourage the players to make use of these instabilities, while the enemy freaks out about her/his lair/base/etc. falling apart and any lower-level participants (whether or not they are "minions") run around trying not to get crushed/burned/etc. instead of attacking the PCs.
This solution is better, in that it doesn't require a retcon and doesn't "really" require the buy-in of the PCs. It's not perfect, though, because you could *probably* still come up with SOME kind of special case scenario where there are NO extenuating circumstances, NO possible venue-related benefits, NO resources the players can draw on, etc. I would think such a fight would not be particularly good to begin with (since, IMO, the terrain should always be *at least* as interesting as the people you're fighting on it!) but I admit that it is a *possible* scenario.
3. If some of the party has plausible ties to higher powers or could plausibly have caught their interest (gods, demons/devils, primal spirits, powerful organizations, what-have-you), have one or more of these groups come in to save the day. Perhaps even have *each individual person* get a special moment--unseen by the other players--during which someone or something offers aid. Perhaps the party Wizard has long been snubbed by the elites at the Academy, but now--suddenly, *suspiciously*--they offer their aid in her hour of desperate need, if she will agree to do a...service...for them. The religious party members could get a divine mandate: You must live, there is a task appointed to you that you have not yet completed! (But perhaps they do not actually know who it is--a message delivered by an angel could come from almost any god...) Maybe the Fighter hears the call of all his ancestors: "You cannot pass this way until there is another." Etc.
I consider this best for three reasons. One, it turns what could have been a disaster into an enormous opportunity for roleplay and for players to feel awesome and badass just at the moment they thought they were toast. Two, it allows me (or generically the DM) to tailor entire new, and potentially very open-ended, plotlines for the players: and even *not* doing something for a particular party member could be a plotline all its own! (E.g.: "Everyone else in the party has someone special WATCHING them...why don't I?" Or: "I got powered up too, but no one claimed responsibility--WHO is watching me, and WHY??" Very appropriate for a Rogue, that one.) Three: It doesn't even require the kinda-sorta-semi-retconning of option 2, because it (hopefully) draws upon enough ideas already established in the fiction, and I find it unlikely at best that I would DM for a group that had NO attachments whatsoever to SOME being or group that could intervene.
If push came to absolute shove, and I had ZERO time to prepare/reconvene/fix, and NOTHING could be changed? I would almost surely go with option 1 and re-do the fight at the next session, with profuse apologies. If "next time" weren't an option--perhaps a one-shot kind of thing?--then, and ONLY then, under what I consider pretty "extreme" duress (as much as DMing can produce anything remotely like "extreme duress"), would I even consider fudging--and I would *still* hesitate to do it, and scramble to find SOMETHING else I could do.