Nine-year-old Josh finds it impossible to get along with his rambunctious eight-year-old stepbrother Jake, until an impending change in their family unites them on a common front.
Billy, the former champion slugger for his third grade baseball team, is bothered by his very young stepsister's presence at games and feels that she is jinxing him into a batting slump.
Jake Raven, expecting to dislike her new stepsister and stepbrother, ends up helping them protect an alien from another dimension as he flees from mysterious pursuers with the ability to alter time.
Four new stepsiblings move from London to an out-of-the-way English village, where they discover a book--inhabited by a grouchy bookworm--that promises to make the reader a wish-granting genie.