Yuka is a married woman who lives with her husband and her brother-in-law, Mamoru. One day, Mamoru, who has been an unsuccessful actor, finally passes an audition for a play. However, when Mamoru is shy and worries about the "kissing scene," Yuka says, "I'll help you practice," and kisses him... Before long, Yuka becomes engrossed in Mamoru's passionate kissing, not knowing what to do, and she extends her tongue and entangles it. From then on, telling herself, "It's just acting practice," she and Mamoru kiss, and the curtain rises on a play where it's just the two of them...