Partly affected by my own experiences, Yun is 7 years old. He has serious Asthma since he was born. He can not leave the ward without doctor's permission. But he is very optimistic to his disease.
Instead of watching TV, Yun's favorite hobby is watching the clouds and day dreaming. He is fond of reading nature science magazine (only the pictures) and guessing clouds with Fei. Fei (meaning fly in Chinese) is a 6 years old girl who shares the same ward with Yun.
Yun always believes he can fly, though doctor told him it's just his daydream. One day, some people (maybe god) tell Yun that Fei will lose her life in seven days unless some one can clean the air and clouds around. Yun started his dream travel to save his best friend......