Laila and her husband arrive for a week's holiday in Greece in desperate need of a reset.

As Laila sits by the pool she finds herself inexplicably drawn to the other family staying in their resort.

Em has no idea who Laila is, or that she has been watching her and her teenage sons and husband so intently.

Five days later Em's world will be blown apart by a horrifying event.

Laila thinks she knows the truth of what happened. But in telling Em what she's seen, she stands to lose everything she holds dear.

And what if she's got it wrong?