Time Travel in a campaign! DM help!

[The Anarresti]

So, I am DMing a Real Life campaign that involves time travel. The game has (or is supposed to have) a horror-esq tone. I've got a very group, consisting of an Archivist, Assassin-type Rogue, and a guy who is playing a homebrewed class called the Free Runner, the basic premise of which is a person who not only is extremely acrobatic and mobile but can also sense distortions in the space-time continuum and actually bend space and time to his advantage.
On a whim, I sent them back to a land of the dinosaurs. I have little idea of where to do from here. I don't want this to fall into a gimmick, I'd like to have there be a lot of secrets of the ages and mysteries of the universetm. I was also considering having a "time cops" type organization, but that seemed a bit of a hackneyed plot.
Anyway, any advice on how to incorporate time travel into a campaign? How would paradoxes work, etc? How can we keep dramatic tension if they can go back in time to fix anything that happened?

[Golkiwu]

To comment on the Dinosaur Time Period...

You could:

-Have a "Bad Guy" Free Runner/group attempting to place items in the past to be re-discovered in the future wrong time (placing cashes of Modern/Future weapons to be uses in early wars in history to change the outcome).

-Complicate the previous suggestion, or another one in the time period with an imminent extinction level event. You could even have the other guy/group trying to thwart the extinction event in some way to keep dinosaurs around.

- be cliche' and go all Jurassic Park on them.

-Another bit I can think of is from a book I read when I was younger (can't remember the title). The bad guys were slowly changing the present by planting a unique and powerful item in the past and going back to get it in a later past time. this was flooding the present with multiple instances of the unique and powerful item.

:smallbiggrin:

[lord pringle]

Have them run into themselves from a bad future. Then make the second to last combat be them versus bad future them who have been brainwashed the whole time. Then they fight the thing that made them evil. Have them win but make them question if they are under the thing;s control. Then after the fight without saying a word get up and end the session. They will love and hate you.

[DoctorGlock]

You can have the villain change small and almost unnoticeable but previously observed details in the PCs past creating small localized paradox which slowly tears the PCs between divergent possibilities.

Make sure you preserve cause and effect, if the PCs enlist future selves they have to remember to go back and help past selves.

Cause/Effect is the biggest thing to remember when running these kinds of games. I played in one last year, and we had some rather amusing fun. In one case we were to examine how a major artifact belonging to the god of time wend missing. The conclusion I came to was that we stole it. Cue DM confusion as I detail my plan to leave myself the artifact, use it as the focus to a time travel spell to go back and steal the artifact, then remember to go back and give it to myself to avoid paradox (It also happened that I was stealing it from my future self in the first place, but the game got a bit confusing at points).

Once you add time travel however the game looses a sense of urgency since you can always pop back and fix your mistake. Then you have to find real reasons for a PC to need to warp to prehistoric Nantucket right now. The game I was in used some rather heavy handed approaches: Paradox caused temporal turbulence that made travel to affected regions difficult to impossible and paradox began altering the universe retroactively so if you do not act now there is no then to fix. In some cases we had to return to far before the paradox and leave thing waiting as nasty surprises for the paradoxers to prevent them from causing paradox (and we had to keep alot of paperwork to preserve cause and effect and avoid paradoxing ourselves)

[Diefje]

It's better to steal a good idea, than to come up with a bad idea.

If you don't want to deal with paradoxes, you can make every jump take them to an alternate timeline universe that will have an alternate future. This way they can't accidentally unmake their own existance, but they cannot EVER return to "the normal world" if they change something in the past. Kind of like the Krenim timeship thingy in Star Trek Voyager.

[limejuicepowder]

Anyone ever read the Animorphs series? Completely kick-ass, even though it's meant for early teens.

Anyways, in one of the books the group of characters got sent back to the time of the dinosaurs. However, they quickly discovered two rival groups of aliens battling for control of the area. To make a long story short, they teamed up with the "good" aliens to defeat the other group. When they succeed, the bad aliens take off from Earth, but leave a parting gift: they redirect a comet that would have missed the Earth to instead hit the good aliens' colony. The good aliens have but a single explosive device left that is strong enough to break up the comet, but knowing what is supposed to happen (because they are from Earth, after all), the main characters disable the device. The comet hits, wipes out all evidence that aliens ever came to Earth, and set in motion the extinction of the dinosaurs, thus allowing humans to eventually evolve.

I find this type of time travel plot to be the most intriguing: things would have turned out differently (and changed the known future) had the characters NOT been in that time and taken the actions they did. This may or may not be suitable for a DnD campaign because if characters don't take the "right" course of action things can still get really screwed up; I guess it depends on what kind of PC's you have and what their goals are. Still though, I think it has great "o ****, that's what that's about!" value.

[NNescio]

You can have the villain change small and almost unnoticeable but previously observed details in the PCs past creating small localized paradox which slowly tears the PCs between divergent possibilities.

Make sure you preserve cause and effect, if the PCs enlist future selves they have to remember to go back and help past selves.

Cause/Effect is the biggest thing to remember when running these kinds of games. I played in one last year, and we had some rather amusing fun. In one case we were to examine how a major artifact belonging to the god of time wend missing. The conclusion I came to was that we stole it. Cue DM confusion as I detail my plan to leave myself the artifact, use it as the focus to a time travel spell to go back and steal the artifact, then remember to go back and give it to myself to avoid paradox (It also happened that I was stealing it from my future self in the first place, but the game got a bit confusing at points).

Still paradoxes. (http://en.wikipedia.org/wiki/Bootstrap_paradox) See, most forms of Time Travel already violate causality in umpteen dozen ways, so you might as well throw cause and effect out of the window... since well, such a universe can no longer be 'causal'. (http://www.schlockmercenary.com/2005-04-03)

[DoctorGlock]

Still paradoxes. (http://en.wikipedia.org/wiki/Bootstrap_paradox) See, most forms of Time Travel already violate causality in umpteen dozen ways, so you might as well throw cause and effect out of the window... since well, such a universe can no longer be 'causal'. (http://www.schlockmercenary.com/2005-04-03)

No, we still had to create the artifact at some point to avoid bootstrap paradox. it just involved alot of trips to put everything in the right place. time. thing.

[Abies]

So, I am DMing a Real Life campaign that involves time travel. The game has (or is supposed to have) a horror-esq tone. I've got a very group, consisting of an Archivist, Assassin-type Rogue, and a guy who is playing a homebrewed class called the Free Runner, the basic premise of which is a person who not only is extremely acrobatic and mobile but can also sense distortions in the space-time continuum and actually bend space and time to his advantage.
On a whim, I sent them back to a land of the dinosaurs. I have little idea of where to do from here. I don't want this to fall into a gimmick, I'd like to have there be a lot of secrets of the ages and mysteries of the universetm. I was also considering having a "time cops" type organization, but that seemed a bit of a hackneyed plot.
Anyway, any advice on how to incorporate time travel into a campaign? How would paradoxes work, etc? How can we keep dramatic tension if they can go back in time to fix anything that happened?

The only way to "realistically" keep dramatic tension would be to have the players act as the "Time cops" ie: "If {EVENT} does not happen per "xyz parameters" you will have never existed... (then rocks fall, but way worse).

Time Travel is bad, very bad, when not allowing for alternate infinate universes.

[kardar233]

I like having players go back and change something, and then have to work against themselves (http://thepunchlineismachismo.com/archives/631) to fix what went wrong (http://thepunchlineismachismo.com/archives/284).

[Lonely Tylenol]

Creating, maintaining, and closing time paradoxes and time loops is all about self-reference. If it doesn't come full-circle, it hasn't resolved itself. Remember that the resolution of a time paradox can come earlier in the timeline than its inception, which results in answers without questions, which can itself raise questions.

Here's a thought exercise that you might actually want to make into a campaign:

Have the party face off against future versions of themselves. The future versions came back to their point in the timeline (in the dinosaur age, whatever; the setting is arbitrary) to confront them, saying that their actions here irrevocably ruined the timeline and that they must be stopped to preserve causality... But their future selves are scarred, have burns or physical deformities, or their identities are hidden, or they are geared or obscured in such a way that makes them unrecognizable to the PCs. They fight, and the PCs kill their own future selves. After doing so, they unmask their assailants to discover that they killed their future selves.

They're left to settle this dilemma:

They did, or will do, something in the timeline that dramatically affects the course of history in the universe you have created... But this isn't it. The event of killing themselves was a normal part of the timeline, because their future selves could not come from the future to announce a timeline-changing event and simultaneously create it (they would have to have been there the first time to create the event, before ever getting to the point where it changed their future). Obviously, don't tell them this information; let them figure it out for themselves.

Let them travel out to the divergent path they've forged for themselves that their future selves came to confront them about, if they so choose. If they go back, let them continue to try to solve the puzzle; if they don't, let their absence be what changes the timeline (they were NOT involved in a particular event).

If they return to stop their future selves from confronting their past selves, they run the risk of fundamentally changing the nature of the timeline from what was originally pre-ordained (which is that the future selves came back to punish their past selves for ruining the timeline), but after a point that the events were set in motion (their future selves had already returned to the past to confront their past selves). If they fight their future selves at this point, it fundamentally changes the timeline, because their past selves never fought their future selves, so their past selves are able to traipse about dinosaur land undeterred until they perform whatever action fundamentally changed the timeline in the first place (provided your group didn't do that already with the second fight), which causes your future selves to return to fight your past selves; the timeline that they are in becomes destabilized and collapses in on itself, because the loop that it created excluded itself.

If they go back to the past to prevent their past selves from ever getting to the point where they end up fighting their future selves, then it fundamentally changes the timeline in a way that prevents the entire chain of events from ever happening, thus closing the loop safely and preventing whatever event fundamentally changed the timeline in the first place. However, if they don't handle the situation well, then they may end up having to fight their past selves, and if they do that, of course, they cannot win, because if they kill their past selves, they annihilate themselves, because they could never have existed up to the point where they could go back in time to fight themselves. If they end up fighting their past selves and lose, then their past selves embark on a journey to find out why their future selves came to prevent them from altering the time line, and repeat. A stable time loop is created that perpetuates the chain of events.

The cool thing about this adventure is that you could start again from "our intrepid gang of adventurers enters DINO-LAND" over and over again, each time creating a stable time loop that feeds itself or an unstable time loop that collapses itself, until they get it right and prevent all future loops from being created. You also get the opportunity to produce a true self-fulfilling prophecy through causality in time/space, as well as to write a story that starts at the conclusion and tries to work toward an introduction.

CAUTION: May wind up a bit railroady, although that might be what your game is like anyway, since you're talking about space-time paradoxes, and those things don't just happen in a party-directed sandbox.

CAUTION II: It's 5 AM here, so a lot of what I'm writing may not make sense, but try to do with it what you can.