淫らな兄嫁に誘われて ～欲求不満熟女の特別授業～

A certain summer.
For Mamoru, a student preparing for college entrance exams, it was an important time.

During this summer, his older brother came home for a visit with his wife, Yumi.

When Mamoru met Yumi for the first time, he was struck by her beauty and thought to himself, 'I didn't know such a beautiful person existed in this world.'