In the middle of summer vacation, Aya, who is the advisor of the swimming club, is at a training camp with her students. Contrary to Aya's enthusiasm for the national tournament this year, her students, Ariki and others, are only interested in Aya's swaying huge breasts, estimated to be J cups. Instead of concentrating on club activities, Ariki and others are busy peeking at Aya changing clothes and showering. Their evil schemes don't stop there, and they plan to confess their feelings to Aya and have a nighttime rape. That night, Aya notices Ariki and others' plan at the last moment and scolds them. However, her voice does not reach the excited students, and she is forced to resist in vain...