Sousuke and Sachiko are plotting to bring together Keiji and Mari, who have a subtle relationship as acquaintances and neighbors who get along well. Today, they invited them to their home to drink, but Sousuke, who was drunk, began to flirt with Sachiko in the bedroom, trying not to let the two people on the other side of the wall notice. Keiji and Mari, who had fallen asleep, became aware of the atmosphere...