Axe discovers a trap set for him by Taylor. Chuck and Wendy navigate marital issues. Wendy rekindles an unlikely friendship. Taylor pursues a new business venture. Connerty formulates a plan to go after Chuck.
As Elizabeth prepares to leave the state department and announce her run for president, anti-globalist terrorists attack the United Nations delegation in Geneva who are there to sign the climate migration treaty.
Kara and Lena head to Stryker's Island to search for clues on how to defeat Lex. At the prison, Kara tries to befriend a nosy prisoner, Steve, who may have insight into what Lex was doing, while Lena studies an array of puzzles Lex left behind in the hopes of discovering his whereabouts. While there, a prison riot breaks out and Kara must find a way to stop the prisoners without revealing her secret identity as Supergirl. Meanwhile, Kelly encourages James to talk to someone for his PTSD, and Alex faces off against Ben Lockwood after he storms the DEO and acquires some powerful weapons to hunt Supergirl.