Emily and Jake are the perfect couple. Or so everyone says. But Emily just read a letter that has shattered her perfect world. Now she only has one thing on her mind. Which one of her friends is sleeping with her husband?

I return home to our beautiful house on a chilly winter evening expecting to find my handsome husband Richard waiting for me by the fire. We’re still so in love, and he always takes care of me. He usually comes straight back from work. But tonight, our antique clock ticks on through the dark evening, with no sign of him. Then a knock at the door shatters my perfect life. A 12-year-old-girl, Alice from the village, has been found unconscious in the field behind our house. They say she was last seen getting into Richard’s car.

I nearly threw the letter about the inheritance away with the recycling. Late for work, worrying about how I would afford new school shoes for Kate, I just assumed it was a mistake. But perhaps moving to a new home in a quiet seaside town would be the fresh start we both need. Away from the school bullies making Kate’s life a misery, and out of the clutches of my dangerous ex. 

When I arrive unannounced at my husband's studio in need of a shoulder to cry on after hearing that my best student, Alex, has died, I see a pair of wineglasses drying by the sink, and my deepest fear is confirmed: my husband is having an affair. Most women would fall to their knees in tears and throw him out of the house - but I just can't bring myself to do it. Instead, I go home and cook a healthy dinner for our children, walk the dog, and unload the dishwasher without complaint. I need this marriage to work to protect a terrible secret of my own....

Ava only left her daughter in the pushchair for five minutes. The buckle was fastened, and she was sure it was safe. But when she came downstairs, the door was open and Abi was gone - she walked down the road, past the Lovegoods' house, and was never seen again. A year later, the Lovegoods throw a housewarming party, showing off the results of their renovation. Ava doesn’t want to go. She can’t bear to look down that end of the road, to see the place where Abi vanished, and she doesn’t want to spend time with people who don’t share her grief. 

Fran finds her standing by the swings. A little girl, Esther, no older than seven years old, by herself in the dead of night, her pretty but old-fashioned yellow dress covered in grass stains and her hair dishevelled. She says she's waiting for Father, and that strikes Fran as particularly odd. After Esther is reunited with her family, Fran can't stop thinking about this pious child whose imaginary friend is God. Fran's instincts tell her something is very wrong. Why does Esther keep running away from home, and how did she get that bruise on her leg? 

For 15 years, Lexi and Jake have played the same six numbers with their friends. Over drinks, dinner parties, and summer barbecues, the three couples have discussed the important stuff - kids, marriages, careers - and they’ve laughed off their disappointment when they failed to win anything. But then, the unthinkable happens. There’s a rift in the group. Someone is caught in a lie. And soon after, six numbers come up that change everything forever.

Gen is on the verge of a divorce from her cheating husband. When her sister, Meg, has a convention to attend in the Big Apple, she invites Gen along to celebrate her newly found freedom. But the perfect sisters’ getaway quickly goes awry when a tipsy Gen defiantly throws her wedding ring off the hotel room’s balcony. Then, wanting some fresh air, she decides to take a late-evening walk alone and vanishes without a trace.

Leah’s perfect marriage isn’t what it seems, but the biggest lie of all is that she’s learned to live with what happened all those years ago. Marie drinks a bit too much to help her forget. And Carly has never forgiven herself for not keeping them safe. 

What was my sister doing standing over Florence’s cot in the middle of the night?I trust my sister, Carrie, with my daughter’s life. But then she’s accused of a terrible crime. Carrie lives under our roof, she pushes my daughter on the swings, she takes her out for ice cream. You might ask, why do I let her? Why would I risk my darling baby? How could I let my sister stay? Because I have a dangerous secret too. One that only Carrie knows about. And if that secret gets out, I could lose my little girl....

Cassie stares at the woman on her doorstep in disbelief. Just months after losing her only son, Josh, here stands a stranger claiming to be Josh’s girlfriend. But it’s not only the woman Cassie is shocked by, it’s the baby nestled in Kim’s arms. Cassie’s grandchild. I know what you did. As Cassie tries to do what’s best for baby Samuel, she starts to receive threatening messages from someone from her past - someone Cassie has been hiding from for a long time.

You're not who you say you are. Neither is she. She thinks she knows me. She believes my marriage is falling apart at the seams, that my husband can barely look me in the eyes. She thinks I’m desperate for a baby, that my longing for a family keeps me up at night. As much as I hate to admit it, all of this is true. She thinks I listen to her advice, that I care about her opinion. That couldn’t be further from the truth. Because she has no idea who I am. She has no clue that I know everything. I know her secret. I know that she did the unforgivable. I know how many lives she ruined.

Pete Riley answers the door one morning and lets in a parent's worst nightmare. On his doorstep is Miles Lambert, a stranger who breaks the devastating news that Pete's son, Theo, isn't actually his son - he is the Lamberts', switched at birth by an understaffed hospital while their real son was sent home with Miles and his wife, Lucy. For Pete, his partner Maddie, and the little boy they've been raising for the past two years, life will never be the same again.

It was supposed to be the happiest day of her life. Zoe was sitting in her hotel room, in her perfect white dress, looking forward to the moment when she would make kind, handsome Toby her husband. Then, there was a blank. They said she must have fainted, overcome with emotion. But nothing felt quite right afterward. Did something happen in that missing time? 

January 1992. A baby girl is left alone for a moment. Long enough for a mother to dash into a shop. Long enough for a child to be taken. Thirteen years later, solicitor Robert Knight's stepdaughter wins a place at a prestigious London school for the gifted. The only puzzle is his wife Erin's reaction. Why is she so reluctant to let Ruby go? Doesn't she want what's best for her? As Erin grows more evasive, Robert can't help but feel she has something to hide and when he stumbles on mysterious letters, he discovers she has been lying to him.