Max, a first-class thief, steals a magic ruby that has the power to change the world, as well as give life to all those who have no heart: the toys. In order to get it out of the country, Max hides the relic inside a teddy bear, called Boom, which is very popular among children.
Accidentally, the Boom bear with the hidden ruby ends up in the toy store. Max, who will do his best to get it back, manages to get hired as a night watchman at the store and starts a fun chase in which he will end up learning to behave and be a good boy.
Has he also stopped being a professional thief thanks to the magic of the ruby?