Deep’s presents Deepthroat Exclusive: Momosaki Miiro. Desperate to be with his younger sister Miiro, the brother secretly films her every day and repeatedly confesses his love. But Miiro, who despises her brother, ignores his feelings. One day, after breaking up with her boyfriend, she reluctantly agrees to date him—just for one month. That single phrase pulls her into a forbidden relationship with her brother. What follows is a secret affair they can never reveal to their parents. Gradually, Miiro finds herself drawn into her brother’s heart, falling deeply in love until she can’t imagine life without him. Yet, this relationship begins to cast a dark shadow over her brother’s soul. After leaving home for a while, he suddenly returns—with a fiancée. How will Miiro face this heartbreaking moment?