Nadia and her mother move to Epiphany because Nadia's mother and father have just gone through a divorce. Epiphany, which is in upstate New York, is where Nadia's mother grew up, and she wants to return there because she says "she need(s) some autumn in her life". When her mother and father were together, the family lived in Florida. New York is a long distance away from Florida, and has more distinct seasons than its southern counterpart. Nadia says that in Florida, when school starts in the fall, it is still a "de facto summer" no matter what the calendar says.
It is possible too that Nadia's mother wants to be in a place where she can adjust to the upheaval in her domestic situation comfortably. Returning to the security of the place where she grew up, a place in which the changes of seasons are visible and tangible, might help her get used to the changes in her own life (Chapter 2).
Nadia and her father cancel their trip to Disneyworld because Nadia's grandfather has asked for their help in saving a batch of newborn baby turtles. A northeaster has hit the coast right at the time the turtles were born, and unless the little creatures are harvested and helped to resettle in their proper environment, they will die. Nadia's father wants to keep his Disneyworld promise to his daughter, but Nadia convinces him that it is more important that they help with the turtles. She likens the need the turtles have in resettling to their own situation in having to adjust to the divorce (Chapter 2).
Julian Singh now lives in Epiphany because his father has bought Sillington House and is converting it into a bed and breakfast inn. Julian's parents had worked on a cruise ship for most of Julian's life, but now that Julian's mother has died, Julian's father has decided that he and his son should "settle down". Julian's father, who is a chef, has always wanted to own an inn, and so they have settled at Sillington House in Epiphany (Chapter 6).