The story tells the adventures of the boy, 21 emon, engaged in the management of a hotel belonging to his family for years. In his problems, 21 emons is helped by the robot Gonsuke and the little alien Monga.

Pen-Pen, the hat-and-tie-wearing prince of Penguin Land, turns up unexpectedly on little Mika's doorstep. and invites himself and his zany friends to stay.