Callen and Sam work with Navy Captain Harmon “Harm” Rabb, Jr. to locate a group of ISIS sympathizers aboard the USS Allegiance. Also, Hetty enlists her friend, Navy Lieutenant Colonel Sarah “Mac” Mackenzie, to help obtain information from a Russian diplomat.
Lex Luthor descends upon Washington, D.C. and summons Lena and Lillian Luthor to the White House. Supergirl realizes she has one last chance to stop Lex and turns to the power of the press to help her.