Ruka, a young girl in a foster home, feels abandoned and often clashes with other kids. When she runs away in search of her parents, she encounters a teenage boy in trouble. After a heartwarming gesture from the boy with her lost plushie, Ruka learns the painful truth about her deceased parents. Overwhelmed, she wishes to find the kind man she met earlier. A strange phenomenon transports her to a pool club where she meets Joe, the man from before. To her astonishment, she has transformed into a teenager. As she navigates this mysterious new world, Ruka's bond with Joe takes unexpected turns.