Hiro Hamada is a 14-year-old high school graduate and robotics genius living in the futuristic city of San Fransokyo (a portmanteau of San Francisco and Tokyo) who spends much of his free time participating in illegal robot fights. To redirect Hiro, his older brother Tadashi takes him to the research lab at the San Fransokyo Institute of Technology, where Hiro meets Tadashi’s friends, Go Go, Wasabi, Honey Lemon, and Fred. Hiro also meets Professor Robert Callaghan, the head of the university’s robotics program. Amazed, Hiro decides to apply to the university.
To enroll, he signs up for the school’s science fair and presents his project: microbots, swarms of tiny robots that can link together in any arrangement imaginable using a neurocranial transmitter. At the fair, Hiro declines an offer from Alistair Krei, CEO of Krei Tech, to market the microbots, and Callaghan accepts him into the school. At the end of the day, a fire breaks out among the exhibits and Tadashi rushes in to save Callaghan, the only person left inside.