My soon to be 4 year old twins have not seen any of the Toy Story films yet but we thought it would be a good idea for them to see at least one prior to our trip to WDW in September. Any suggestions as to which one would be the best for their age? If I recall the first film, Woody saves the toys who are tortured by the boy next door. My DH is concerned that may be too dark for our preschoolers. Thanks!