Cooro is a Plus Anima, a boy with the ability to use animal powers (in his case, those of a crow). On his quest to find another Plus Anima, he comes across a circus that has a mermaid on display at the sideshow. He gets caught sneaking in without paying, and is captured by none other than the mermaid, who happens to be a fish Plus Anima boy, being made to dress as a princess. Husky, the fish boy, originally planned to have Cooro take his place at the circus, but the ringmaster thwarts his plans of escape, so Cooro rescues him and they escape together. In the village of Abon, Cooro and Husky meet the bear Plus Anima, Senri. Senri is guarding the field of Abon grass from the Garrison Group, who wants to dig it up for gold. Unable to wait for the village to give permission, the Garrison Group blows up the field, and finds out there's no gold there anyway. Senri also discovers that this is not the plant he's looking for, and decides to travel with Cooro and Husky. The three of them come to the town of Octopus, where they are pick-pocketed by some little girls.
While chasing the girls to get their possessions back, Husky gets his pearls stolen while Senri ends up saving one of the little girls who stole from them. They meet the leader of the thieving girls, who lets them stay because of Senri's kindness, and agrees to help Husky get his pearls back. As it turns out, Husky's pearls were stolen by a bat Plus Anima, a girl named Nana. They pearls are lost in the end, but Nana, after settling a dispute with Husky, is allowed to join the other Plus Anima in their travels.