One morning in the Tsukuda household, Hanpeita's sister, Tsukune, lets his pet bird escape out of spite. On the way home from school, she finds a strange egg from another planet and brings it home to give her brother, in order to make up for her earlier mistake. However, he isn't too pleased with it.

Not too long after, the egg swells up, cracks its shell, and out comes a pink, strange chicken-like alien creature named Ganmo! He speaks like a human being and comes to live with the Tsukudas. Not wanting to be a mere freeloader, Ganmo takes the initiative to run errands, clean the house, and do other menial chores, yet he blunders at everything he does. Everytime Ganmo tries to clear his reputation his efforts end up causing even more confusion.

A charming young, purple-haired girl named Ayumi Ichigaya moves next door to the Tsukudas. She has a strange pet myna bird named Déjà Vu. It's foppish with a poisonous tongue and always teases Ganmo for being so odd-looking.

And so begin the messed up daily lives of young Hanpeita and his new pet.

(Source: Wikipedia)