Chii is a athletic and happy girl who saves a younge boy's life after he falls down a flight of stairs. To repay her, he gives her a peice of bittersweet chocolate. When she arrives at her elementary school she learns that he is a new transfer student from Tokyo. She then begins falling in love with him. Then, the next day he dies unexpectidly. Still, Chii tries to deny it. All she has left of him is the chocolate rapper and a diary that he wrote. in it, Chii learns that he loves her.