Ryan Reynolds is actually a godlike being who created multiple universes and put himself in as a character in each one. Susan is another being like him who is trying to get him to leave the world he created. He eventually does so by pulling off the green thread around his wrist, causing reality to collapse. He creates a new world for Margaret and Noelle with a new father, which is supposed to be the 'best of all possible worlds'. Noelle tells her mother that he isn't coming back.