In a labyrinth of abandoned service tunnels below Temple Underground Station, Daniel Milton (Mark Strong), a highly respected surgeon, runs an illegal medical clinic that treats criminals and other desperate patients who cannot or will not seek help from regular medical facilities. Daniel sets up the clinic to find a cure for his wife, Beth (Catherine McCormack), who suffers from a terminal illness. Lee (Daniel Mays), a Temple station staff member, and Anna (Carice van Houten), a medical researcher, help him run the clinic. The series focuses on the secrecy, exits and issues of trust as the clinic treats its patients as well as Daniel's need for money to fund his research.
