In American-Japanese mash-up locale San Fransokyo, Hiro is a brazen, fast-talking kid inventor who is squandering his potential, and it's his older brother, Tadashi, who wants to steer him toward being a more productive member of society.
Baymax comes into his life, too, and when "forces of antagonism" rise and a mystery develops in the city, Hiro turns his squishy, soft and pliable robot meant for a career in health care into an armored fighting machine ready to save the day, Williams says. "As he's doing that, they form a relationship and a bond that Hiro wasn't counting on."
The youngster also forms a heroic team with his big bro's talented teen friends: adrenaline junkie Go Go Tamago, neat freak Wasabi No-Ginger, master of chemistry Honey Lemon and resident fanboy Fred.
They do have a long way to go before they're the Avengers, however — instead of superheroes, these kids are super-nerds, according to Hall.