mouseferatu has a good recent article about
plot
So the concept of plot isn't a bad thing. making it a choke chain of 1 path to success is a bad thing.
So following my vague example:
let's say the PCs really want to find Uncle Ned, the wayward sorceror. Maybe he's just lost and hasn't been heard from in a while.
The plot hook is "an NPC reveals some information about a recent Ned sighting"
If the party pursues it, the plot is "stuff the PCs do to find Uncle Ned"
The complications are: Uncle Ned seems to have gotten it into his head that he can channel the power of the dormant volcano across the desert to re-animate his dead girlfriend. Apparently he's been dabbling in necromancy since he's been gone.
So now you know the places this plot will need: a desert and a volcano where presumably the party will find Ned. You can make it dramatic and have their arrival be on time to confront him during the ritual, or you could make it all Volcano of Dr. Moreau and have him greet them warmly, but act a bit secretive about his operations there.
You'll probably expect the party to provision themselves, so Al'Bob the camel guy and probably a guide and some suppliers.
Sprinkle in some random encounters for along the way, and you've covered the basics for an adventure to find Ned.
Once you start the game, obviously the PCs will have to decide to pursue Ned to use all this material.
From a sandbox perspective, Ned's volcano is going to blow up and nuke this town with ash in X number of days. From a narrative perspective, Ned's not doing this stuff until the party pursues the plot hook, so it really doesn't matter.
In either case, once they pursue the hook, the party MIGHT go rent some camels. Or the party might teleport. That's not really the GM's problem. He's provided 1 means, and the party is free to think of an alternative that he will adapt to. it is no big deal if the party skips some random encounters.
When the party gets to the volcano (well, if they don't die or something), play Ned like a man obsessed with something). he's distracted, but still, good old Uncle Ned. he might even SHOW the party what he's planning (after all, they're like family). With any luck, the party will figure out that this ritual is probably not safe, and try to stop it. Most likely it'll be at the alter on a ledge over the volcano. But it might also happen in the dining room, nice and safe. It's OK. it's entirely possible they simply talk Ned out of doing the ritual.
Effectively, the plot for this hook is "go find Ned and hopefully stop him from blowing up the volcano in a stupid ritual"
i don't normally use hooks that dire, as they tend to force player action (save the day or die because the day will end horribly).
You could also have made the hook reveal Ned has been held captive at the volcano by canibals whho intend to BBQ him in a ritual over its smokey lava.
Either one has a sense of built-in purpose (we like not dying in a volcanic erruption and we kind of like Uncle Ned which is why we walked all this way to find him).
I don't see whats so hard about it. But then, I only plan for about 4-6 hours of entertainment and assume the matter will be wrapped up during that time.
I expect the hook to be personally interesting to the players/PCs. Note, I chose Uncle Ned, a figure of some personal value to the PCs. i could have chosen some stupid NPC that only another NPC could love.
I do tend to expect the PCs will get involved. That's a risk in my method. But I try not to get bound up in the details of the solution. They party might fight Ned, talk to him. They might even agree that he has an excellent idea, but there's something they need to fetch from home, about 1 volcano's blast radius away.