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.

After the team returns from a mission, Zari finds herself trapped in a time loop that results in the Waverider blowing up over and over again. Zari soon begins to suspect that the answer to stop what is happening might lie hidden among her fellow shipmates' secrets. But in investigating them she starts to understand her place on the team.

After Constantine breaks the cardinal Legend rule—you can’t change the past—he, along with Charlie and Zari try to deal with the ramifications without telling the rest of the Legends. Even though Zari encourages them to just fix the problem, Constantine and Charlie are determined to find another way, but only continue to make things worse.

Ray plans a date night for him and Nora, but all goes awry when an Encore shows up making the team think on their feet and create a lie to keep the Encore at bay. While trying to fool the Encore, Ava learns what Sara was really doing while she was away and confronts her. Charlie and Constantine make a deal to work together, which will benefit both of them. Meanwhile, Rory is upset when he gets negative comments about his book, so Zari helps track down who the critic is, and Rory gets more than he bargained for.