A cat--presumably a stray--is found by a girl who decides to take care of him. Later on, after he begins to trust her, he finds her standing in the rain and asks if she's alright and if someone hurt her. When he doesn't get an answer (personally, I think she died), the cat licks her, runs away, crosses the street, is hit by a car, and dies.
The mentioning of a white flower makes me think it's a crysanthmum, which are used in small Buddhist shrines (for home) signifying the loss of a loved one.