The Legends are all disappointed and hurt by Gideon's actions, but Gideon is horrified when AI Gideon tells her about Gary. Itching to get back to doing what they love best, they realize that Gwyn has broken the treaty and must find him. Meanwhile, Sara keeps an important secret from Ava because she doesn't know how she will react.
Sara starts to realize her team is making questionable choices when it comes to the timeline. Trying to figure out who is behind everything, Sara discovers some harsh truths.
After Sara, Ava, Behrad and Gary arrive in New York City, they track down Dr. Gwyn Davies, who isn't the scientist they expected. Astra, Spooner, and Gideon are still trying to stop the Legends from using the time machine, but they run into some more setbacks along the way. Meanwhile, in the pocket dimension Nate and Zari work together on the Hoover situation as well how to make their future together work.
With Astra, Spooner and a now-human Gideon trying to save the Legends, Gideon becomes overwhelmed by her new human choices sending her into a catatonic state. Astra and Spooner combine their powers to enter Gideon's mindscape and discover that a virus is trying to erase all of Gideon's memories. Acting fast, they devise a plan to defeat the virus before it's too late. Meanwhile, the Legends are about to go up against a powerful new foe.
When heroes alone are not enough ... the world needs legends. Having seen the future, one he will desperately try to prevent from happening, time-traveling rogue Rip Hunter is tasked with assembling a disparate group of both heroes and villains to confront an unstoppable threat — one in which not only is the planet at stake, but all of time itself. Can this ragtag team defeat an immortal threat unlike anything they have ever known?