Ordinary young couple Gemma and Richard have just bought their first home and are expecting a baby. It's all very exciting, and the couple settles in nicely to their new pad. Except for the screaming and shouting they hear at all times of the night through their walls from the house next door. Listening more closely, pregnant Gemma is convinced that she's also hearing cries and smacking noises, which she is certain are the sounds of a toddler being abused. She and Richard have seen the child just once, but not since. Feeling morally obliged to act, the couple gather as much information as possible about what's going on next door. And after social services say there's nothing to worry about, Gemma becomes increasingly obsessed and she starts to spy on them in a way that raises questions about who is actually committing the crime — Gemma's neighbours, or Gemma?.