Yusaku's father remarried and Niina became his new mother. Yusaku was quickly drawn to the kind and sexy Niina. He wanted to get closer to her somehow. Then he got the good news that his father was going on a three-day company trip. He'd be able to be alone with Niina, who he'd always loved... He wanted to use this chance to build a close relationship with her, but he couldn't think of any concrete way to do it and was in trouble.