All of the zoo animals watch as Alice carries a small canister into the reptile house while wearing a bio suit.
The animals go into the reptile house to find out what it is. They see the canister inside a glass cage and it slowly opens and out comes a small frog.
All the animals think he is cute. Private tries to talk to him, but realizes that they can't talk to him because of the glass cage. The penguins remove the glass and the frog goes free.
The frog says his name is Barry and he demands that the animals do whatever he says. The animals laugh at this, but then the laughter stops when Barry touches Rico's foot and Rico is suddenly covered in spots and falls unconscious.
The penguins take Rico back to their headquaters, where Kowalski finds out that Barry is a poison dart frog, who's skin is covered with a toxic slime, and the penguins think of a plan to get Barry back into his cage.
Meanwhile, Barry causes havoc around the zoo by stealing Phil and Mason's bananas, stuffing them in the elephants' trunk and shooting them back at the two monkeys.
The penguins capture Barry by trapping him in a glass and placing a brick on top of it. But as Skipper gives out a big speech about the trap, Barry escapes by digging his way out and then infects Kowalski.
Barry then creates more havoc by forcing the gorillas to have a tea party. Julien arrives and demands Barry to stop bossing people around, because that's his job. Barry is about to infect Julien when Skipper whacks him with a huge bamboo stick. Skipper swings the stick more times until Barry clings to it and tries to infect Skipper. Skipper and Private run away in fear, but Barry catches up to them and Skipper is infected.
Seeing his friends in bed sick, Private realizes that he is the only one who can stop Barry, but he doesn't know how. It isn't until Private sees Mort stuck in a can of beans that he gets an idea.
Private creates his own aromured suit that protects him from Barry's poison. Private then picks up Barry and does what he wanted to do when he first met him, give him a hug. Barry admits that he's never been hugged before and admits that he likes it.
The other penguins awake, feeling much better after the toxin surpasses. But then they see Barry playing checkers with Private, who is still in his aromured suit, and they think that they are still infected and are hallucinating and they go back to bed.