"I wonder what she's up to?" Ichiro muttered in the bath. One night, while his wife was away on a trip, his sister-in-law Yumi came over. He was confused by her sudden visit, unable to understand her intentions... "Shall I wash your back?" Yumi came in naked. It seemed as though Yumi was planning to seduce Ichiro and use him as an outlet for her sexual desires. He couldn't betray his wife, especially not his sister-in-law. Ichiro desperately tried to use his reason to refuse, but Yumi smiled seductively and pressed her body against him...