A couple's dream holiday turns into a living nightmare when they realise that they don't even know each other. David Telfer takes his ex-model wife Louise on a Meditteranean cruise to celebrate her recovery from serious depression. But as they sail across the high seas he begins to have doubts about her state of mind. He suspects, from her erratic behaviour, that she is hiding something from him. Indeed he believes that she may well be harbouring some dark secret. His suspicions are heightened yet further when they reach the beautiful city of Barcelona and his nightmare really begins.