On board a cruise ship in the Mediterranean, Kimberly wakes to discover that her two-year-old son Robert has vanished from the cabin overnight. She and her husband Jason vow to do whatever it takes to bring Robert home.

But he is never found.

Forty years later, their therapist daughter Lily welcomes a new client into her home. Zach has a shocking theory about what happened to her brother Robert years before.

If Zach is to be believed, someone out there knows what happened on that ship. And they would do anything to stop the truth getting out.

But secrets always find a way to reveal themselves...