Josh Hurley keeps a dark secret. He's addicted to the pills that killed his father. When Josh and his mom move to Sunset Beach, Josh expects his life will continue its downward spiral. He doesn't expect to write to his dad in a strange mailbox on a remote shore. He REALLY doesn't expect that his dad would write him back.Irsa Salid keeps a secret of her own. She yearns to surf the waves of Sunset Beach, but knows her strict, religious father would never allow it. Forced to hide her passion, Irsa sneaks to the water for the solace only the waves provide. But that's the thing about secrets: they never stay hidden for long.
When Josh's pill supply gets cut off, he knows it's only a matter of time before his shadows claim him for good, and helping Josh uncover who is leaving the mysterious letters puts Irsa at greater risk of being discovered by her father. The two of them, along with Irsa's Star-Wars-obsessed little brother, strive to discover the truth behind the Kindred Spirit mailbox before their secrets destroy them both.