After losing his family in a tragic accident, high school student Taiyou Asano struggles with social interactions. His only connection is with childhood friend Mutsumi Yozakura, part of a powerful spy family. When Mutsumi's brother Kyouichirou, fiercely protective and dangerous, targets Taiyou, he must wed Mutsumi for safety. As Taiyou delves into the secretive world of spies, he aims to shield his wife and unveil hidden truths about his past and the enigmatic Yozakura clan.