UNMASKING A NEW THREAT — When it's discovered that The Hollow has employed a mysterious servant to do its bidding, Klaus and Elijah host an elaborate party in order to lure the new threat out and uncover its identity. Feeling a sense of responsibility for The Hollow's resurgence, Vincent uses his magic to help the Mikaelsons root out this latest threat. Meanwhile, after uncovering information about who may have been behind her parents' death, Hayley turns to Freya to help unlock her memories from that fateful day. Marcel also appears.
- This is the only episode of the season not to feature Hope.
- Vincent begins to find a pattern to The Hollow's followers attacks over the years and that they are centered on 4 locations in a small area of New Orleans. He connects the Axeman to The Hollow as well as attacks to it to in 1953 and 1992 among other times to it's followers.
- Richard Xavier Dumas, Hayley's father and mother appear for the first time in the series through a flashback. Hayley also appears as a baby.
- Hayley's parents were guarding a piece of the Hollow and they were consequently killed for it by the Hollow's acolytes.
- Dominic, the high priest of the cult is shown to be able to resurrect with the help of his acolytes.
- The Hollow's intentions are revealed to be a desire to be reborn on earth and it needs pieces of its remains to do so, as well as a sacrifice of something powerful such as Marcel
- Papa Tunde's Blade is revealed to be made out of the remains of the Hollow.
- Sofya wants revenge on Klaus because he had killed her family at a wedding 500 years ago.
- Josh discovers where Marcel is despite him being cloaked as he recognized the scent of an ingredient used in cloaking spells.
- Dominic - Heart extraction; killed by Elijah Mikaelson (temporarily)
- 2 of Hollow's followers with Dominic - broken necks; killed by Elijah Mikaelson
- Vincent was last seen in Keepers of the House.
- Josh was last seen in No Quarter.
- The Axeman was mentioned. He was last mentioned in The Axeman's Letter.
- Hayley's mother was seen in a flashback. She was last mentioned in Sanctuary.
- Hayley's father was seen in a flashback. He was last mentioned in I Hear You Knocking.
- Richard was seen in a flashback. He was last mentioned in I Hear You Knocking.
Behind the Scenes
- "Bag of Cobras" is a song by Better Than Ezra.
- Elijah: "This enemy is a dark force and cannot be bargained or reasoned with. I don’t bargain and I am done with reason."
- Klaus: "It's such a shame that these lovely linens will soon be red with blood."
- Sofya: "I can deal with Klaus; you will find Marcel."
- Klaus: "Maybe I should just kill you?"
- Sofya: "Try it."
- Klaus: "Let's go find the viper in our midst."
- Vincent: "What do you want?"
- Elijah: "Can we at least pretend to be civil?"
- Vincent: "We're supposed to be civil? Does Marcel know that? I'd ask him but I can't find him anywhere."
- Elijah: "It is outrageous, where is that young man's sense of courtesy? Please, invite me in."
- Vincent: "Tell me where Marcel is."
- Elijah: "Detained until we can be sure he is free of this thing's vile influence."
- Vincent: "God, you Mikaelsons, you always find a way to get right back on top don't you. And I bet you got a plan all figured out."
- Elijah: "As a matter of fact I do. A rather festive one. Let me tell you about it."
- Vincent: "Well if you're going to help me fight this thing. You're going to have to know what it is you're up against. Come in before I change my mind."
- Elijah: "Wonderful."