An anaconda transfers to the Central Park Zoo and animals begin disappearing.
The Hoboken Zoo has transferred an anaconda (inaccurately called a boa constrictor throughout the episode) to the Central Park Zoo. The Penguins report this to the rest of the animals, but Marlene and Private suggest that the snake could be nice. The next morning, while entertaining the humans, Private distracts them while Skipper, Kowalski and Rico listen to Kowalski's recorder that one of the lemurs are missing. The Penguins left where the humans can't expect.
The Penguins visit King Julien's habitat. Mort goes missing until King Julien's overreaction of his smoothie reminds Maurice that King Julien asked Mort to get some pineapples in the Reptile House. The Penguins enter the Reptile House and find the newcomer, Savio. Savio acts innocent. Kowalski finds a keypad that opens Savio's glass cage and while trying to break the locks, it is invulnerable.
At the Penguins' Habitat, Skipper and Kowalski look at the map to see if all the locks are locked until they found an air vent. Kowalski informs with Mort in his belly, it is impossible for Savio to slip through the vent. They hear a scream from King Julien. They come in to his habitat and King Julien says that Maurice was gone in his sleep. They then hear Marlene scream, but when they come in, she is gone. Rico finds a dried snake skin so the Penguins come in the Reptile House. Rico tries to explode the locks, but to no avail. Savio continues to act innocent.
At the Penguins' Habitat, the Penguins realize that Marlene, Mort and Maurice are mammals. Skipper then realizes that Savio has diet for mammals. At the Zooveneir Shop, they dress Private as a monkey as bait. At the outside, Savio begins to crawl by Private, but it is actually just a hose with snake colors. Kowalski tries calling Private, but he just disappears.
Skipper, Kowalski, Rico and King Julien walk in the Reptile House and accuse Savio again. Savio crawls part of him through the air vent, types the code on the keypad and opens the glass cage. The Penguins and King Julien start running, but Savio catches up and swallows Julien whole. Inside Savio, King Julien is swooped down to Savio's stomach with Marlene, Private (still in the monkey suit), Mort and Maurice (who is furious). Skipper plans something so he, Kowalski and Rico starts running (belly-sliding). They block a trash can on the way, but Savio crawls over it. They block the hot-dog stand, but Savio kicks it out of the way. They serpent around tables, but Savio also serpents around. They jump in Burt's Habitat and Burt beats up Savio by slamming him around. He pulls the pressure by the habitat walls and he vomits the others out.
The next morning, Alice ships Savio back to the Hoboken Zoo.