A scuba diver gets a treasure chest with a picture of a stag, then Ray and Winston are doing work on the Ecto-1. Ray mentions that a treasure hunter named Max Palopolis opened up a maritime museum with an exhibition of 600 gold dubloons.
Meanwhile, a ship notices some unusual fog and is then fired on by a pirate ship. The Ghostbusters get called to the wrecked ship, and Egon discovers a "latent" PKE reading. Peter finds the crew tied up and sees a parrot go through a wall. Then, they find a skeleton pirate captain named Jack Higgins, who declares that he and his crew will "take back what's rightfully theirs". Ray realises that these pirates are the ghosts of the crew of a pirate ship called the Stag, and that their ship isn't the real ship but a ghostly projection of it.
The Ghostbusters try to catch the pirates, but the pirates escape and throw them into the sea. The Stag then "sails" into New York, where the pirates pillage the city. Ray then realises that the box Max Palapolis took must have belonged to the ghosts. Then, the car slows down, which turns out to be because Slimer was in the engine.
Some pirates mug a strangely-dressed man from Houston for his clothes (which include a cowboy hat), some mistake mannequins for real women and flirt with them, and others eat food from a grocery store. The Ghostbusters go to the maritime museum and ask Max Palaopolis to hand over the dubloons, but he refuses.
The Stag shows up, and the Ghostbusters fight the pirates (with Slimer fighting the parrot) and eventually trap them and the Stag. Then, they take Slimer for ice cream, and Slimer also takes the Houstan man's cowboy hat.
This episode provides examples of
- Admiring the Abomination: Upon realising that the pirates are ghosts, Ray geeks out about it being similar to a previous case.
- Broken Pedestal: Ray used to idolise Palapolis, so he's disappointed when he's rude to him and the others.
- Dem Bones: The pirate ghosts resemble walking skeletons.
- Dressed to Plunder: The ghost pirates wear the stereotypical pirate garb, like bandannas and torn jerkins.
- Evil Laugh: Captain Higgins does an evil chuckle during the second fight.
- Exorcist Head: Captain Higgins turns his head 360 degrees in one of his first scenes.
- Feathered Fiend: The pirate ghosts keep an aggressive ghost parrot.
- Food End: Downplayed — Slimer is eating ice cream at the end, but the Ghostbusters aren't eating.
- Ghostly Animals: The Stag crew keeps a ghost parrot.
- Glowing Eyes of Doom: The Stag's mast has eerie, glowing, blue eyes.
- Instantly Proven Wrong: Max Palapolis says he'll protect the treasure at all costs — only to run off when the pirates show up.
- Mass "Oh, Crap!": The Ghostbusters all look nervous at once during both fights with the Stag crew.
- Oh, Crap!: When the Stag crew first shows up, Egon looks nervous, then Winston says nervously, "Guess who's coming to dinner!".
- Pirate Parrot: The ghost pirate crew has a ghostly parrot as a pet.
- Pop-Cultural Osmosis Failure: Though Max Palapolis is famous, Winston is confused when Ray mentions him.
- The Pratfall: In the shipwreck, Peter is knocked onto his bottom.
- Quaking with Fear: Max Palapolis shakes in fear when the Stag shows up.
- Screw This, I'm Outta Here: Max Palapolis runs away when Higgins and his crew show up.
- Talk Like a Pirate: Captain Higgins speaks in a stereotypical West English "pirate" accent.
- Theme Music Power-Up: The theme tune plays during the climactic fight.
- This Is Gonna Suck: Before the second fight with the ghost pirates, Egon says, "I have a bad feeling about this".
