Between the Devil and the Deep Blue Sea

Klaus confronts each faction and threatens them over Hayley's disappearance. Freya visits Hope, who is back in school, to find that she has been searching for Hayley herself. Klaus and Marcel act on a tip-off, but Hayley is gone once again. Angry, Klaus kidnaps a member of each faction and threatens to kill them if Hayley isn't found. Klaus informs Marcel that Elijah is gone. Hayley's crescent birthmark is sent to Klaus, and he flies into a rage and kills two of his hostages. Vincent intervenes before he kills Josh as well. With Klaus now bound, he and Marcel determine that vampires are behind Hayley's disappearance. Greta continues to resist Marcel's leadership, and Hope shares her fears with Roman. As each funeral is held for those Klaus has killed, they declare war on him.

Plot summary from Wikipedia (CC BY-SA 4.0). Source