Sick of Julien's annoying presence, the penguins decide to take a vacation on The Moon. After Marlene is frightened by a spooky noise in the night, she and Skipper travel down to the sewer below the zoo to find the source of the scary moans.

When stuffed Mort dolls become popular at the zoo, Julien gets jealous and get them recalled. Maurice bribes the zoo animals to celebrate "King Julien Day" by offering them candy.

Marlene discovers a lost egg, and asks the penguins to care for it and keep it safe. Jealous Julien wants to raise the egg to be his second in command. When Skipper steals the batteries to Julien's stereo, he sets off a wild chase around the zoo.

The penguins compete against the lemurs in a game of capture the flag. Mort is kicked out of the lemur habitat after he touches King Julien's feet one two many times. So, the penguins take him in and attempt to break him of his foot obsession.

When the zoo installs web cams to bring in new visitors, Private accidentally becomes an Internet star. Skipper accidentally causes King Julien to lose his beloved crown. The penguins go on a dangerous mission to retrieve the crown from the sewer.

Marlene goes over to meet the newest zoo animal, but she mysteriously disappears. The penguins and lemurs try to rescue her, but they are taken, too. When Julien is taken to the infirmary for acting weirder than usual, Maurice is left in charge.