National Treasure-class big-breasted married woman swapping - Secret offline meeting of a married couple's public website -

One day, Takeru, a husband who loves his wife, Yumi, but is suffering from a desire to be cuckolded and is worried about him, shows him a website for exchanging marriages and reveals his worries to Yumi. Yumi was confused, but she ended up going to an offline meeting held by the website for her husband on a one-time promise. When they receive a lecture from the organizer Sakurai, the two couples switch their wives and husbands, and end up indulging in unprecedented lewd sex.