After being marked by The Hollow's dark magic, both Klaus and Marcel experience the symptoms of a malevolent haunting, forcing the two adversaries on a violent collision course. Meanwhile, Hayley and Elijah head out to speak with Mary after Hayley uncovers a mysterious link between the dark magic and her former wolf pack. Finally, as an exhausted Freya risks her own life to cure Klaus' infection, a guilt-ridden Keelin must decide whether to honor her hypocratic oath and help Freya – or flee the Mikaelson's forever.

Freya places a protection spell on the compound when it's discovered that the Hollow's latest servant is on the loose, but it forces Klaus, Hayley and Hope to remain inside. Meanwhile, Elijah takes matters into his own hands when Vincent is reluctant to perform a dangerous ritual needed to strengthen their defense against the Hollow; and Freya enacts a risky plan that brings her face to face with their latest threat, but an unexpected twist leaves her life hanging in the balance.