Two sets of parents divorce and marry each other, while their children Miki and Yuu are caught in the middle and start falling for each other.
Miki's lying in bed in the school's nursery after being hit in the face by a ball, supposedly asleep when Yuu comes in. Yuu asks her if she is asleep but she does not answer, so he looks at her as she sleeps. Then he kisses her and leaves. As soon as he has left, Miki jumps up, surprised and wonders what he is up to, since they have just met... or have they?