Handa Masayuki and Mayuka have finally gotten married after seven years together. Today, they're moving into their new home, and Mayuka's sister, Natsume Sasa, has come over to help out.
While they work, Sasa pushes up close to Masayuki and suddenly says, "I've loved you since we first met."
Sasa approaches Masayuki and kisses him, but he tries to pull away to avoid being discovered.
Just then, Mayuka enters the room. Masayuki and Sasa hurriedly fix their clothes and pull apart. Mayuka doesn't seem to suspect anything when Sasa acts like nothing happened.
Unable to resist Sasa's charms even if it means betraying his wife, Masayuki begins his secret affair with Sasa.