Called away from his wife's memorial service, surgeon Daniel Milton must act quickly to save a criminal's life. But working from an illegal underground clinic is not without its challenges. Daniel seeks solace at a patient's bedside-but whose is it?

A complication forces Daniel to put his wife Beth's former colleague Anna into an impossible position. With knowledge of the underground clinic growing, how much longer can Daniel's secret stay safe?

Working among London's seedy underbelly is not without its cost, forcing Daniel to question just what kind of man he really is. Meanwhile, forces on both sides of the law begin their hunt for Jamie and the robbery money.

Daniel and Anna's relationship becomes complicated as they rush to find answers. But will they achieve their goal before it's too late? Inspired by a brush with love, Lee decides to take a risk that may endanger them all.

Daniel's depravities reach a new low as he descends even further into London's criminal world. As the heat rises and gangster and police forces both close in, will an error from Jamie have disastrous effects?

Struggling with his actions, Daniel begins to spiral. Relationships at the bunker begin to unravel as officers Moloney and Hall get a break in the hunt for Jamie. Daniel faces the question of how far he's willing to go for someone he loves.

Lee reaches a low point-putting the clinic's very existence in danger. A last minute solution proves too tempting for Daniel to pass up, leading him to cross a line even he can't come back from.

Keith and Mercy inch closer and closer to tracking Jamie down. Meanwhile, Daniel is forced to confront the dangerous consequences of his actions. Lee, Anna and Daniel explore how far they'll go to save themselves.