With Rory and Ava at odds, Sara tries to come up with a way for them to get along, but all is put on hold when a new magical creature attacks the Legends. Constantine is forced to confront his tragic past but it could have devastating consequences for the rest of the team. Meanwhile, Mona has a crush on someone she works with and gets some advice from Nate.

When the Legends hear that Mona has let a fugitive go, they must head to 1961 Mexico City to clean up her mess. Mona tries to convince the Legends and the Bureau that the people responsible for releasing the fugitive were some mysterious Men in Black and not her. With no evidence to back up her theory, the Legends must decide if they should trust her and go against the Bureau. Meanwhile, Nate and Zari go on a recon mission to find out what Hank might be hiding from everyone.