Saeko remarried a year ago to a man with a child, and became the mother of a university student, Manabu. One day, Manabu told Saeko with a smile, "Mom, I've decided to join an event club." Saeko hoped that Manabu's university life would be a fruitful one... Then, a few days later, Manabu came over to her house with his club friends. The group was plotting something evil for the summer event. Then they came up with the idea of getting Saeko to drink the "original drink" they had invented...