The story happens at a fictional city named San Fransokyo. There is the home of an infant prodigy, Hiro Hamada and his special friend, Baymax – a snow man robot. With his intelligence, he makes many fighting tools for the band of high-tech heroes – the Big Hero 6. Despite the ignoring of the police, they together investigate “the strange bugs” and find out the scheme destroying the city. A devastating event befalls the city that police have to ask for help of the band. Can Hiro and his friends save the city?