Chibi-Robo is a four-inch-tall rechargeable robot whose sole purpose is to make its owners happy. Accompanied by its talkative guide Telly Vision, Chibi-Robo makes its way through the dysfunctional Sanderson household, trying its best to make the family members happy. It won't be easy though - their daughter thinks she's a frog, the wife is furious at the husband for wasting money and makes him sleep on the couch, and, if that wasn't enough, there are reports of spider-like robots out to destroy Chibi-Robo!
Chibi-Robo!: Plug into Adventure! is a platform adventure with a difference - players control a small robot, whose short size means that regular objects like furniture and stairs become gargantuan obstacles for it to overcome. Its battery is consistently draining while not plugged into a wall outlet, and its power consumption increases when it uses tools like its blaster, copter, or radar. Because of this, players must keep an eye on their remaining power and regularly recharge.
The aim of the game is to earn Happy Points to increase Chibi-Robo's rank and become Super Chibi-Robo. This can be achieved by performing simple tasks (such as throwing away trash or cleaning floor stains like muddy footprints) or by making its owners happy, for example by giving a rose as a gift to Jenny, the frog-obsessed daughter. This role-playing aspect of the game is similar to the gathering of "love points" in Moon: Remix RPG Adventure.
Also similarly to Moon and some of its spiritual followers (such as Giftpia), the game world is populated by rather exotic characters, all of which talk in a mysterious gibberish language, with subtitles displayed on the screen.
The family dog Tao in the game is in fact Kenichi Nishi's own dog (who passed away in 2009). Tao appears in many games designed by Nishi; his first appearance is as Grandma's dog in Moon: Remix RPG Adventure.