Pinoko becomes friends with a boy named Cinque. When she gets home, the letter she starts to write is a love letter. Curious, Black Jack asks her who the man is, but she refuses to tell him. After this, Pinoko goes on a date with Cinque, but Black Jack is not impressed. Treated like a child, Pinoko decides to become an adult and starts to act grown up by wearing makeup and adult clothes. Then, on the night of their umpteenth date, a sick person is brought into Black Jack's house. It turns out to be Cinque...
