There's chaos in store when Sebastian invites the Large children to his sleepover! When Mrs Smart promises Sebastian a special treat for getting top marks in his music exam, there's just one thing he wants: a sleepover with Laura, Lester and Luke. Mrs Smart is horrified - with the Large children involved, things are guaranteed to get out of hand! This time, however, it's Sebastian who's having all the accidents - breaking the new TV, messing up his mum's designer wardrobe and spilling paint on the carpet. When Mrs Smart blames her unwanted guests, Laura, Lester and Luke are sent back home. But Sebastian hasn't given up on his sleepover - it will just have to be at the Large house instead, where anything goes...and that's far more fun!