Season 1 of Timeless has taken us to major historical events before, such as President Lincoln's assassination and the Hindenburg disaster. While they've faced enemies along the way, none have been as dangerous as those in this episode, "Party at Castle Varlar," as we're introduced to some of the most vile villains in history: Nazis. Our favorite time-traveling gang must travel to 1940s Germany to stop Flynn from potentially handing over the atomic bomb to Hitler's army.