College student Kanade visits his girlfriend Aimi's house for the first time. There he meets her sister Kaede, who is cute, free-spirited, and accidentally shows off her huge tits through her clothes. Her massive tits make him fully erect. Noticing his excitement, the mischievous sister starts teasing him with her G-cup tits. "They're bigger than my sister's... won't you fall for me?" Unable to hold back, Kanade gives in to his desires and fucks her every day. He gets off on the taboo thrill of fucking his girlfriend's sister.