I Hear You Knocking

S4, E5: After being marked by The Hollow’s dark magic, both Klaus (Joseph Morgan) and Marcel (Charles Michael Davis) experience the symptoms of a malevolent haunting, forcing the two adversaries on a violent collision course. Meanwhile, Hayley (Phoebe Tonkin) and Elijah (Daniel Gillies) head out to speak with Mary (guest star Debra Mooney) after Hayley uncovers a mysterious link between the dark magic and her former wolf pack. Finally, as an exhausted Freya (Riley Voelkel) risks her own life to cure Klaus’ infection, a guilt-ridden Keelin (guest star Christina Moses) must decide whether to honor her Hippocratic Oath and help Freya – or flee the Mikaelsons forever.