Only Hank Zipzer would think of holding Christmas in the middle of summer and only Hank's family would agree to let him do it. Soon Hank's imagination runs out of control and he's inviting Mr Rock to join the yuletide fun and planning to get a cow to dress up as a reindeer. Will Emily's perfect planning save Hank from another disaster? And can Mr Rock's unexpected guest, Miss Adolf, really save the day?