Seihai, the aunt who came to Tokyo for a job training session, ended up staying at her nephew Seihei's apartment. Seihei was captivated by the beauty of his first love, Seihai, whom he hadn't seen in a long time, and couldn't suppress his pounding heart. Just then, an unexpected intruder appeared between the two! Seihei's friend Matsunaga fell head over heels for Seihai at first sight and aggressively started pursuing her. Seihei felt that if things continued like this, Matsunaga might take Seihai away from him…
