Tsukasa moves into her relatives' house after being transferred for work. She meets her younger cousin Ami for the first time in 10 years, and she's still the same serious and plain girl she was in middle school... But when she peeks into Ami's shower, she discovers an unexpectedly voluptuous and sexy body! Taking the chance to be alone with Ami, she starts making lesbian advances, and the sensitive and shy girl with glasses reacts in an unexpectedly lewd way... A silly and lewd lesbian drama about incestuous relationships!