The story takes place in a fictional city called San Fransokyo (an abbreviation of the two cities of San Francisco in the US and Tokyo in Japan). It is the home of the genius boy Hiro Hamada and a very special friend named Baymax. Baymax looks like a white snowman, an invention of Tadashi - Hiro's brother. Baymax was created to serve human health. With Hiro's intelligence, the boy created combat tools for the superhero team with the companionship of the other 5 members: Baymax, Wasabi, Go Go, Fred and Honey Lemon. Together, they investigate the "kabuki" who stole Hiro's "micro-bug" invention and prevent a disaster for the city.