: Marcel is haunted by visions of Elijah and Klaus, who goad him to finally seize his revenge against the Mikaelson family for their centuries of betrayal.
: Freya risks her life to create a cure for the infection the Hollow placed on Klaus, solidifying her bond with Keelin as they work together to protect the family. Key Revelations [S4E5] I Hear You Knocking
" I Hear You Knocking " is the fifth episode of the fourth season of the CW series , which originally aired on April 14, 2017. This pivotal hour serves as a psychological deep dive into the show's two most complex power players, Klaus Mikaelson and Marcel Gerard, as they are forced onto a violent collision course by a malevolent entity known as The Hollow . Psychological Warfare: The Hollow’s Manipulation : Marcel is haunted by visions of Elijah
: The Hollow manifests as his abusive father, Mikael. These hallucinations taunt Klaus, suggesting he is weak and that the only way to protect his daughter, Hope, is to revert to his most brutal, murderous self by killing Marcel. This pivotal hour serves as a psychological deep
The episode also marks a significant shift in the relationship between Freya Mikaelson and her captive-turned-ally, Keelin.
: Though the intended sacrifice failed, the Hollow accepts Marcel’s blood and grants his allies a magical thorn capable of killing an Original.
: Hayley discovers that her parents were murdered by Mary’s husband while he was under the influence of the Hollow.