One of the most compelling plots in any game in any genre is the use of time travel. It can be one of the most complex plotlines and can cause countless arguments among players and GMs of what the possible effects can and will produce; not to mention countless rounds of headaches.
Most of these arguments arise from the knowledge of what changing the past will cause to the future. Most of the knowledge and theories are seen in countless movies and Star Trek episodes. The problem is there really isn't any "one true" effect in time travel. After all, they ARE theories.
How can one argue which theory is right? We can start a argument here right now and go to bed with a headache. If one travels in time to change the past which would change the future, then travel back to the point in time where he began, how will he convince anyone that he did indeed change the past? For the past happened as it happened to the people of the timeline he just changed.
Let us try another theory. The past never changed, for when he changed the past, another alternate quantum reality was created. The original reality he was in never changed so no one really knows if he was successful and if he was to land himself in the new alternate reality, no one knows about it either; because the past happened as it happened in that reality.
Asprin? So even if we do discover time travel and wanted to go back and change anything, how will we know it actually worked? Other than to the time traveler(s), we poor sods sitting in our known reality would just have to take their word for it upon their return. Or lock them up because they insisted that they stopped World War I; yet we had no record of World War 1.
For all we knew, we sent them in time to stop the creation of Barney, the Purple Dinosaur because our children who watched it grew up to be psycho stalking killing machines. So the mission was a failure to us and it is time to scrap the multi-billion dollar project. All it did was make our guys looney and was a complete waste of money and time, (No pun intended), and we still have the problem with psycho purple-painted-faced stalking killers.
So we will drop that argument of "Is time travel possible?" and instead take a look at the theories that can help you come up with new and inventive plots for your games. Now, we will be looking at travel BACK in time. Maybe in a future article we will talk about cause and effect for traveling into the future, because it opens a whole new can of worms.
Remember, time travel plots can be possible with any genre since time exists everywhere. The trick is coming up with an excellent adventure with time travel.