The Sandersons employ Chibi Robo as a simple maid-bot, but things get exciting when Mr. Sanderson (the man of the house) mysteriously severs his position at his robotics company. Now, the nefarious Spydorz of Macroware Robotics, Inc. constantly assault the once-peaceful home of the Sandersons, and Chibi Robo is their last line of defense. As point-droid in this battle for casa de Sanderson, Chibi must battle the Spydorz with the aid of the various non-human residents of the house including the family dogs, random children's toys, and whoever and whatever else he can coax into action.
Of course, Chibi has a bottomless well of abilities from which to draw aid. Special attachments such as the Chibi-Copter (which allows Chibi to tool around the house free from gravity's shackles) and the Chibi-Blaster (a sonic cannon ideal for the obliteration of grit and grime) help Chibi Robo accomplish his impossible mission. When things become too challenging for this literally pint-sized powerhouse, Chibi can gain the assistance of his housemates by wearing different costumes. When Chibi dresses up as a dog, he can talk to the dogs; donning a frog frock allows him to speak with amphibians; and sporting superhero tights grant him the support of Space Hunter Drake Redcrest (one of the many toys in the house).