Mayor Lenny is giving a speech in front of an Irish castle in Central Park that was relocated to New York by a guy named Warner Applegate III. Then, pipes and drums start playing in the castle, so Lenny sends his aide Milo in to check it out. Milo gets thrown into the moat, so Lenny sends the police, but they also get thrown in the moat. Reporters ask if the castle is haunted, and Lenny denies and tries to investigate, but a gust of wind blows him away.
He calls the Ghostbusters, who arrive, and Lenny explains that Applegate got the castle from a lord named Liam Kildarby, who was down on his luck. When the Ghostbusters enter the castle, Ray is picked up and thrown in the moat by a ghost. He then reveals that the ghosts are all subservient to a leader and looks them up, determining they're the ghosts of the original Lord Kildarby and his men, who were killed in a surprise attack.
Peter asks to see Lord Kildarby, calling himself "O'Venkman", and asks why he keeps throwing everyone. Kildarby says that he's getting rid of "intruders". When Peter reveals the castle has been moved to New York, Kildarby angrily chases Peter and his servants surround the rest of the Ghostbusters, but back off when Ray threatens to destroy the castle.
The Ghostbusters then try to negotiate with Kildarby, but it doesn't get very far, until (at a servant's suggestion) he makes a wager: either defeat his pet bird, or leave the island. They think he means the small island the castle is on, so they accept, but then he reveals he means Manhattan as a whole. Then, the giant bird arrives and starts attacking, and it's too big to trap.
Luckily, they manage to lure it to the firehouse, where Ray links a trap to the containment unit, which succeeds in trapping the bird. The Ghostbusters then return to Central Park and explain to the Mayor that they allowed the ghosts to stay, however, they had them promise not to bother the tourists... during the day.
This episode provides examples of
- Antagonist Title: The eponymous bird is the baddie.
- Bittersweet Ending: The bird is locked up and the ghosts have sworn not to bother the humans during the day... however, they still cause problems at night.
- Duck!: When the Ghostbusters tell Janine to duck, she thinks they're calling the Bird of Kildarby a duck.
- Ectoplasm: Played for Laughs when Janine is grossed out by Slimer leaving slime on her hand after a handshake.
- Evil Laugh: At one point, Kildarby is heard laughing devilishly.
- Feathered Fiend: The eponymous bird is a large, evil bird with humongous claws that it attacks with.
- The Food Poisoning Incident: Discussed when Peter sees Egon looking scared about the bird and asks, "Is it something you ate, old buddy?".
- Glowing Eyes of Doom: The Bird of Kildarby's eyes light up before it attacks at one point.
- I Don't Think That's Such a Good Idea: Winston is the least on board with agreeing to the bet.
- Instantly Proven Wrong: First, Lenny claims the castle isn't haunted, right before being blown away.
- Left the Background Music On: Played for Horror — Pipe music can be heard... which then turns out to be being played in-universe... by ghosts.
- Nocturnal Mooks: The ghosts agree to only cause bother at night.
- Oireland: When Peter is talking to Irish ghosts, he adds an "O'" onto his last name.
- Pun: When Peter is wondering why he didn't have one of his friends instead of him speak to Kildarby, adding "O'"s to their surnames, he follows it up with "Oh boy!".
- Red Is Violent: The bird attacks people and things with its long sharp claws, and it's red.
- Shout-Out: Peter calls Castle Kildarby "Sleeping Beauty's summer home".
- Silent Whisper:
- First, Kildarby's servant unintelligibly whispers in his ear.
- Then, the Ghostbusters can be heard unintelligibly whispering.
- Speak in Unison: When Kildarby says he wants the Ghostbusters to leave Manhattan if they lose, they yell, "Manhattan?!" in unison, since they'd thought he was talking about the small island.
- Spell My Name with a "The": The bird is known as the Bird of Kildarby.
