It's swimming season again in the savannah. But this year, Rose the hippo is shy about showing her curves. She's heard that animals call her "Hippobottomus" behind her back. Under the supervision of Gigi the giraffe and Isabelle the gazelle, she starts a diet, eating only the highest leaves and chasing wildebeests until she's out of breath. All in vain. One day, while her friends are bathing, they are threatened by a huge crocodile. Rose's bulk will be of help!