/// MISSION BRIEFING

A high school girl, Sei Saotome, unexpectedly is transferred to an elite high school in Nagano prefecture due to her parents' house-moving. One day, she meets Mizuki and Taiyo, and is invited to join astronomy club with them. The personalities of two boys are completely opposite from each other. Sei, Mizuki and Taiyo struggle with sorrowful and impatient love-triangle...