Six friends travel to a remote island north of the Scottish Highlands for an old school reunion. They've rented The Lighthouse - a stunning, now abandoned building that was once notorious for deaths at sea.

On the first evening, someone goes missing. The group search all through the night to no avail. But when the five remaining friends return to the lighthouse early the next morning, they are shocked to find James inside. He's looks terrified - but won't say a word about where he's been.

The party vow to put the strange night behind them and enjoy the rest of their stay, but when more unexplained things begin to occur, tensions escalate. It's clear James knows something, but nothing will persuade him to give up the secrets of the island. Is he protecting his friends from a terrible truth, or leading them into more danger?