When mysterious but adorable creatures called Mayoi suddenly appear in San Fransokyo, Hiro is convinced that they're part of some nefarious plot by Liv Amara.
As the new prodigy at San Fransokyo Institute of Technology, Hiro now faces daunting academic challenges and the social trials of being the little man on campus. Off campus, the stakes are raised for the high-tech heroes as they must protect their city from an array of scientifically enhanced villains.