I Hear You Knocking (S04E05)

Klaus and Marcel find themselves plagued by the sinister effects of The Hollow’s dark magic, pushing their rivalry to an explosive breaking point. Meanwhile, Hayley and Elijah seek out Mary after Hayley discovers a troubling connection between the dark magic and her old wolf pack. As Freya pushes herself to the brink in an effort to heal Klaus from his affliction, Keelin grapples with her conscience, torn between upholding her Hippocratic oath to assist Freya or escaping the Mikaelsons for good.