When she was little, Mum used to lie out in fields of flowers and stare up at the clouds. There are no clouds on the Moon. Cosmo realises just how much Mum misses clouds. A mission to Jupiter, the biggest planet in the Solar System, takes the family into the cloudy atmosphere of the gas planet. There, Cosmo has an idea! Cosmo enlists the help of Dad, Sol and GIL to make a garden of paper flowers and set up a very special surprise for her Mum.