Carmen and Nicolai found their son, Tommy, floating in their garden pond, but it was too late to save him. Inspector Skarre arrives on the scene, and Carmen says that Tommy, a healthy toddler with Down syndrome, was playing alone and drowned. But an autopsy reveals that Tommy's lungs are full of soap, prompting Skarre and his trusted colleague Inspector Sejer to revisit the couple. When they return, Carmen, an epileptic, changes her story: she had a seizure while bathing Tommy, came to, and found him dead in the tub. Terrified, she threw him into the pond. But Skarre and Sejer are skeptical. What could Carmen be hiding? And what lengths will she take to cover her guilt?