One morning I glanced out the window and saw a whale floating in the sky. The whale was blue and grey, large and clumsy, yet he was just rolling along and gliding on the warm sunny breeze with surprising grace.

When eight-year-old Cappy discovers a whale swimming outside of his bedroom window, it's fair to say he's quite surprised. Given how long he's spent in hospital, Cappy has had plenty of time to read a LOT of books on animals, and he's never heard of a whale that can fly.

Thanks to his leukaemia, Cappy's used to not being allowed to do things he wants - like eating sweets, playing with dogs, or roaming too far from his protective family - so he's delighted when the amazing whale not only speaks to him, but asks him to join him for a ride in the sky. Soon, Cappy and the whale are the best of friends, and together they will go on an amazing journey of imagination, hope and curiosity.