Welcome to Eldey, an island with deadly secrets.

Mona is a carefree artist, staying at The Cloister to work on her illustrations.

Beth is the harried mother of a toddler, on the remote Welsh island for a weekend escape with her family.

Charlotte wanted a romantic getaway with her husband, not a trip with his troubled teenage stepdaughter.

One of them is a serial killer who poisoned three of her friends at her eleventh birthday party.

When one of the hotel guests is found dead, it becomes clear to Mallory Dawson – the night manager of the boutique island hotel and former police detective – that The Birthday Girl is among them.

Three guests who fit the profile, but which of them would risk everything to kill again?

Six lies killed Huw Jones.

On New Year’s Eve 2010, Huw Jones disappeared from his bedroom while his father and five friends were downstairs. His body was later discovered on the nearby cliffs at St Non’s.

That night, all six friends lied in their statements to the police.

Over a decade later, Huw’s mother, Heledd is found dead.

Mallory Dawson must uncover the lies lurking in the tight-knit community of St Davids. But someone has kept their secrets for years, and they would kill to protect them…