Ten years ago, a father drowned in the Bay of Biscay. His son made a promise that day.

Now twenty-five, Leo Carter is the second officer aboard the Sterling Horizon ? 2,417 passengers, the pride of a maritime empire. But Leo is not here for the view. He is looking for an answer: was his father's death an accident, or something the Sterling Company has spent ten years burying?

A fourteen-day voyage from Liverpool to Lisbon. Rainy decks. False names. A stateroom called A-723. Leo's path crosses with Ava Sterling, an heiress who is not behaving like one. Ava is searching for something too. Or running from it. Or both.

Below decks, a conspiracy is moving. In the executive suite, someone is making decisions. And somewhere on this ship, a person is closing a ledger that opened long before Leo's father ever set foot on a bridge.

A literary thriller about the promise between a father and a son ? and the quiet certainty that the sea returns everything you give it.

For readers of Daniel Silva, Tana French, and Sebastian Faulks.