Legends of Tomorrow follows the adventures of Time Master Rip Hunter. Having seen the future, one he is desperately trying to prevent from happening, Rip assembles a mismatched group of heroes and villains to confront and stop Vandal Savage from taking over and eventually destroying the world.
From the shows opening:
"In 2166, an immortal tyrant named Vandal Savage conquered the world and murdered my wife and child.
I have assembled an elite team to hunt him throughout time and stop his rise to power. Unfortunately, my plan is opposed by the body I'd sworn my allegiance to: the Time Masters.
In the future, my friends may not be heroes, but if we succeed, they will be remembered as legends."
DC's Legends of Tomorrow Ringtone