Asako lives with her sister Kanna in her apartment in the city to attend a university in Tokyo. Kanna seems to get along well with Asako's boyfriend Ryuji and appears to be watching over the two of them, but secretly she had her eye on Ryuji. She then sets a 'trap' for Ryuji, calling him out for her own sexual gratification, but Ryuji becomes unable to bear the guilt towards Asako...
