When Posey’s grandpa announces that he’s marrying Posey’s neighbour, Mrs. Romero, Posey is thrilled! She LOVES Mrs. Romero and she’s going to be the flower girl! But then she learns that Mrs. Romero will be moving away, and her dog Hero, too. That is just about the worst news ever and Posey wants nothing to do with the wedding. Now no one is happy. Then Mrs. Romero has an idea - what if Hero stays with Posey? Posey jumps at the idea, but it turns out that makes Hero even more miserable than she was. Is Posey strong enough to do what will make everyone happy again?