Aisling's two sons, Ethan and Finn, mean everything to her. Ever since becoming estranged from her own parents, though, she's always felt like a piece of her is missing. Desperate to find answers - about her family, and herself - Aisling uploads her DNA to an ancestry website, and is thrilled when it finds a match. But instead of finding answers, she comes face to face with a detective. Aisling's DNA is a match for a recent crime scene - the latest in a string of murders. And the police have two lead suspects: Ethan and Finn. Aisling would do anything for her sons - but can she protect a killer?