Mi Na receives an absurd reply to a message sent to Woo Jae by mistake. Meanwhile, Hee Jae has a big fight with Hyun Woo over masturbation. Hee Jae different from before is a change caused by hormones?

Mi Na visits the hospital for a health check-up and undergoes surgery. Meanwhile, after spending the night with In Chan, Hee Jae finds an unopened condom, and the ovulation day alarm goes off!