This is a scientific fiction movie taking place in the future city of San Fransoskyo. When the film opens, we are introduced to a 14 year boy who is a genius in the field of robotics. He has already graduated from the high school studies at the age of thirteen. Now his main work is to participate in bot fights which are arranged illegally in the city.
He has an elder brother named Tadashi tries to deviate him from this illegal activity. He takes Hiro to his lab in his college- San Fransokyo Institute of Technology for learning advanced things. Hiro meets Gogo, Honey, Fred Wasabi who all are friends of Tadashi. Hiro also sees Baymax the robot designed by Tadashi for the purpose of healthcare. Tadashi also takes him to the head of the robotics department Prof. Callaghan. Hiro is very much impressed after meeting all people at the institute and decides to take his further education in that institute only.