Tập 4: Keita đi nghỉ suối nước nóng cùng các cô gái sau khi nhận vé làm quà tốt nghiệp từ bố mẹ.

4

The sibling's parents give Keita tickets to a hot spring resort as a graduation gift and suggest that he take the girls along on the trip. The siblings go to the hot spring resort, end up visiting an erotic museum, and find themselves in some compromising situations involving Ako's unintentional purchase of alcohol. (Source: Wikipedia)