A batch of toxic bananas has infiltrated the market, zombifying any primate who takes a bite, including Wally. Gus must travel to the bananas' source planet and find a cure for the zombie germ.

Gus and Wally cannot help themselves when it comes to anything round and bouncy—which makes it awkward when Chimpsky entrusts them with the highly explosive BALL (Ballistic and Lethally Loaded).

Gus makes a monster movie and posts it on Space Book (a parody of Facebook). The whole galaxy except YAY-OK and the monkeys think that YAY-OK has a disease because it was viral.

YAY-OK becomes a bully when the monkeys re-wire him.

YAY-OK meets his creator who thinks he is no good anymore and hurts his feelings.

Thanks to the monkeys, Chimpsky loses his job and is demoted to a Jr. Jr. Jr. Rocket Monkey 3rd Class. Gus and Wally take advantage of their 2nd class status and make the former GASI chief do their bidding.

When Yay-Ok starts to feel old, he gives himself a hip new upgrade. However, a misunderstanding causes Gus and Wally to believe that this new robot has killed their old pal, so they put him on trial.

When Yay-Ok's robo-ripener hits Wally, it gives him a mustache, which means he is now the more mature monkey. This makes Gus jealous, especially when the new facial hair causes Monkevil to start falling in love with his brother.

Dr. Chimpsky's nephew visits, but he is not who he says he is.

Lord Peel finds an abandoned baby Hate-a-Saurus and tries to raise it to destroy the monkeys.

Dr. Chimpsky has a party, but no one comes to it. The monkeys and YAY-OK try to turn this around for him.

When Gus's new glasses up his stock considerably, a jealous Wally purchases a questionable knock-off pair, with horrifying results.