In a house in Manchester divided into four flats, we are introduced to four interweaving stories about love, parenthood, loss and self-discovery.
Gail (Alison Steadman) bumps into an old friend who makes a startling observation about Gail's marriage to Henry (Peter Davison).
The ordered life of Belle (Victoria Hamilton, reprising her role from Doctor Foster) is thrown into disarray by the hospitalisation of sister Ruth (Susannah Fielding), and the subsequent arrival of wayward niece Maya (Erin Kellyman).
David (Adrian Lester) goes on holiday without his wife Kelly (Rachael Stirling) and has his head turned unexpectedly by Saira (Saira Choudhry). And heavily pregnant Hannah (Melissa Johns), recently coupled up with Liam (Joshua James), is surprised by her connection with Andy (Calvin Demba), the father of her unborn child, who has been away travelling for the duration of the pregnancy.
These disruptive arrivals turn each person's life upside down, setting off a chain of events which we will follow across the series.