Seventh episode of a nine-part conspiracy thriller, starring Romola Garai. Written by Matthew Broughton. Helen is kidnapped by the organ traffickers she has been investigating. To make matters worse, so is her mother, Rosie. As they wait for death in a tiny room, the secrets between them begin to unravel. What do the traffickers want with them? Will they get out alive? And why won't Rosie talk about Helen's mysterious long-lost sister Elizabeth? Tracks: A story in nine parts about life, death and the human brain. Directed in London by Abigail le Fleming.