Hiro is a young genius in a futuristic metropolis called San Fransokyo and signs up for the school’s science fair. However, a fire suddenly breaks out and kills his older brother Tadashi and devastates his microbots. As a result, Hiro shuts himself away in his room while Baymax, a robot invented by his brother, becomes his only companion. One day, Hiro and Baymax discover someone has been mass producing his microbots. Hiro, together with Baymax and his four close friends, called “Big Hero 6”, determines to uncover the mystery…
　　未来世界的超级都市旧金山，天才少年小宏参加了学校的科技展会。谁知突如其来的一场大火让他哥哥命丧火场，也烧毁了他的发明成果。身心饱受创伤的小宏闭门不出，哥哥生前留下的治疗型机器人大白则成为他的唯一伙伴。谁知小宏和大白竟意外发现有人在大量生产他的发明。小宏、大白与其他四位朋友组成“超能陆战队”，决定揭穿这场阴谋……