It's Saturday morning, and young Yuuta is in high spirits—his father is finally home on summer break, and the two are heading off to the pool together. Left behind at home, Chisato oddly feels upbeat too, and for good reason: as soon as her husband and son leave, she plans to invite her fuck buddy, Kenji, over. The moment they're out the door, Kenji arrives and declares, "Let's have lots of sex today!" With no limits on time or number of rounds, the two dive into their secret affair—kicking off another day of unrestrained pleasure.