A little girl named Charli has a ghost friend, DJ. Charli falls ill with the chickenpox and has to stay inside. A round wooden door appears on her bed, under the sheets Charli and DJ have hung up to make a cubby house. The magical door opens into a tunnel that leads to her brother's cubby house, one he has built with his mates in the backyard. Cooper has been having lots of fun without Charli. But now Charli and DJ have some fun of their own, playing funny tricks on the boys!