When a new Time Aberration is discovered by the Legends, they find themselves headed to 1927 Chicago. The Legends quickly realize that they have been set up by Eobard Thawne, Damien Darhk and the newest member of the Legion of Doom, Malcolm Merlyn. While everyone is trying to help fix what they think is the mission, Jax encourages a reluctant Stein to share his secret with the other Legends. Stein is taken captive and Sara must make the tough choice of either stopping the Legion of Doom or saving Stein. Meanwhile, Rory gets an unexpected visitor and is not sure how to handle it.

When Damien Darhk and Malcolm Merlyn try to capture Rip Hunter in 1967, they create an Aberration big enough to draw the attention of the Legends. However, when the team arrives they discover that Rip has no memories of his past due to “time drift” and is just a graduate film student. After trying to convince Rip of who he was, they discover that he possesses an incredibly powerful artifact known as the Spear of Destiny, which the Legion of Doom is after. Ray and Nate realize that the Aberration has also affected them personally making it difficult to help the team. Meanwhile, Rory asks Stein for help and makes him promise to keep it a secret from the team.

The Legends are determined to find and rescue Rip, but first must focus on locating the Spear of Destiny. Stein thinks he has the perfect person to help but knows involving her will be risky. Meanwhile, Malcom Merlyn and Damien Darhk realize that Thawne is pitting them against each other.

The Legends must devise a plan to retrieve the last remaining fragments of the Spear of Destiny from the Legion of Doom. They find themselves in France at the height of World War I faced with the knowledge that they must destroy the mystical object. They enlist the help of a soldier by the name of John Ronald Reuel Tolkien and find that the Spear is leading them into the heart of the war. Meanwhile, the team must all resist the temptation of the Spear, and the return of a former teammate.

The Legion of Doom rewrites history after obtaining the Spear of Destiny, potentially changing the Legends forever.

When a massive timequake rocks the ship while the legends are preparing for their next destination, they must break a cardinal rule of time travel.