Several years after losing her husband, Nobuko has been raising her son Yosuke on her own. Her cheerful and honest son, along with her late husband's close friend Shunichi, have been her pillars of support. However, one day, Shunichi suddenly disappears. When Nobuko asks Yosuke about him, she only receives vague answers, so she secretly sets out to find Shunichi herself. But upon discovering the truth, driven by a desire to restore their broken bond, Nobuko devises a bold plan of her own.