Matilda has been through a lot. Her mum has run off to Mexico, her boyfriend has dumped her, and her friends have cut their ties.
So when her long-lost father, the famous and reclusive painter Kingsley Cello, invites Matilda to spend the summer at his seaside home, Hidden Beach, there's nothing to stop her crossing the country to see him.
When she arrives, instead of a father, she finds a crumbling house in a state of neglect, filled with mysterious paintings and locked towers, and three teenaged boys:
Meer - her open-hearted, tattoo-obsessed half-brother, who embraces Matilda as a sister, but is hiding a dark secret;
Brock - the damaged, professionally charming former-child star who is dealing with more than just the demons of his past;
and Tatum - sullen, wild, and hardworking - who for some reason wants Matilda to leave Hidden Beach as soon as possible.
With Kingsley nowhere to be seen, Matilda must delve into the twisted heart of Hidden Beach to uncover the answers she's desperately craving. But secrets run thicker than blood, and blood runs like seawater.
And everyone here is lying.