Talented and successful surgeon Daniel Milton has his world shattered when his wife Beth develops a fatal degenerative disease. After conventional treatment options run out, Daniel partners with the lonely yet resourceful Lee to start a literal Underground clinic in the vast network of tunnels beneath Temple Tube Station in London.
In the first series, Daniel just about kept the plates in the air as he looked after his wife, Beth, in an illicit clinic underneath Temple tube station. But now everything comes crashing down as Beth wakes from her coma and demands answers. Eve wants to know why her parents have been lying to her, Lee joins forces with a charismatic activist and Anna is desperate to make something positive out of the situation.