Marissa Irvine arrives at 14 Tudor Grove, expecting to pick up her young son Milo from his first playdate with a boy at his new school. But the woman who answers the door isn't a mother she recognises. She isn't the nanny. She doesn't have Milo. And so begins every parent's worst nightmare. As news of the disappearance filters through the quiet Dublin suburb and an unexpected suspect is named, whispers start to spread about the women most closely connected to the shocking event. Because only one of them may have taken Milo - but they could all be blamed.

It’s March 2018, and the country is covered in snow. Roads are impassable, shops are running out of food, and official advice is to stay indoors. Marianne lives on her own and works from home, so this isn’t a problem. Until she wakes one morning in her house in the middle of nowhere and finds footprints trailing all across her garden. Half-asleep, she is at first curious.

When Sylvia looks out her bedroom window at night and sees a child face down in the pond next door, she races into her neighbor's garden. But the pond is empty, and no one is answering the door. Wondering if night feeds and sleep deprivation are getting to her, she hurriedly retreats. Then Sylvia's little daughter wakes one night, screaming that there's a man in her room. This is followed by a series of bizarre disturbances in the house. Sylvia's husband insists it's all in her mind, but she is certain it's not - there's something very wrong on the other side of the wall. 

Psychologist Margot Scott has a picture-perfect life: a nice house in the suburbs, a husband, two children and a successful career. On a warm spring morning Margot approaches one of her clients on a busy train platform. He is looking down at his phone, with his duffel bag in hand as the train approaches. That’s when she slams into his back and he falls in front of the train. Margot’s clients all lie to her, but one lie cost her family and freedom.

It’s hard meeting your ex after so much time apart. You remember the tears and accusations, the desperate look on his face as he punched the wall, but you try not to show it. You smile politely, even while your heart beats faster. You watch as he looks down into the stroller, at the beautiful blond-haired, blue-eyed baby kicking his little legs in the sunshine, whose innocent smile lights up your world. You see his face change. You know what he’s thinking. The next day he calls. His voice is shaking. He wants the truth. Is it his child?