The four-part series explores the complexity of family dynamics and modern relationships, focusing on three adult siblings, Jake (Russell Tovey), Helen (Claudie Blakley) and Natalie (Lydia Leonard).

When the sibling's recently widowed mother, Vivien (Francesca Annis), declares she is in love with a new man, Mark (Stephen Rea), the family is thrown into turmoil.

Jake, Helen and Natalie's suspicions are raised, with the arrival of Mark threatening not only the large family home overlooking the Sussex coast, but also their inheritance and many happy childhood memories.

When Mark encourages Vivien to shift her priorities away from her children, and brings into question the happiness of her 45-year marriage to the siblings' father, the trio decide to try and find out more information about him, sending them down a dark path of tragedy, and spiralling towards a possible crime.

An added complication comes in the form of Mary (Imelda Staunton), who has lived next door to Vivien for 40 years and has developed an unhealthy relationship to Vivien and her family’s unfolding drama.

As years of secrets, lies, rivalries and betrayals come to light, the siblings struggle to pull together as everything they hold dear is under threat, ready to implode at any moment.

The rest of the cast includes Sharon Small (Trust Me), Keir Charles (Love Actually), Vincent Regan (Victoria), David Bamber (Valkyrie) Stephanie Langton (Law & Order UK) and Clara Indrani (EastEnders).

The series is created and written by Sarah Williams (The Long Song) and directed by Louise Hooper (Cheat).