In an alternate universe, people can only see the color of their soulmate’s eyes until they meet said soulmate, and sometimes, the soulstrings that connect soulmates can be visible if you squint hard enough. Kurokawa Manami, a genius 14-year-old with a high school diploma, has been accepted into a strange job: she has to work as the assistant of the “Head of Otherworldly Monitoring”, who turns out to be another genius teenager, 15-year-old Hoshinomiya Kino. Secretly in hopes of finding their soulmates, Manami and Kino keep constant surveillance on the other worlds and timelines unfurling around them… until one day, suddenly, they see other colors.