Marlowe and Harper share a bond deeper than most sisters shaped by the loss of their mother in childhood. For Harper living with what she calls the Up syndrome and gifted with an endless capacity for wonder Marlowe and she are connected by an invisible thread like the hum that connects all things. For Marlowe they are bound by her fierce determination to keep Harper born with a congenital heart disorder alive. Now 25 Marlowe is finally living her own life abroad pursuing her studies of a rare species of butterfly secure in the knowledge Harpers happiness is complete having found love with boyfriend Louis. But then she receives the devastating call that Harpers heart is failing. She needs a heart transplant but is denied one by the medical establishment because she is living with a disability. Marlowe rushes to her childhood home in Hong Kong to be by Harpers side and soon has to answer the question what lengths would you go to save your sister? Intensely moving exquisitely written and literally humming with wonder it is a novel that celebrates life in all its guises and what comes after.