Barry finally puts the pieces together and figures out who Savitar is in this episode of The Flash. But before that happens, he and the team have to protect the one person who might be able to trap the evil speedster: Tracy Brand.

The only problem? Killer Frost, who is already teamed up with Savitar by the time "I Know Who You Are" begins, is also after her. And while one member of Team Flash may have trouble going up against her, she has no problem fighting her former teammates. Oh, and all of this happens in 16 hours.