Prevention

Ba'al travels back in time and prevents the Stargate program from being started. SG-1 must somehow restore history.

After accidentally crash-landing in 2022, time-traveling fighter pilot Adam Reed teams up with his 12-year-old self on a mission to save the future.

What was a cunning plan from Lord Edmund Blackadder V to fake a time machine on his gullibly incompetent friends, turns out to be the real thing and hurls him and his imbecile underling, Baldrick, through the course of human history.

Three astronomers accidentally intercept what they believe to be a signal from a distant alien civilization, but the truth is even more incredible than any of them could have imagined.