American journalist Ralph Ackerman is tortured and killed, after meeting with Fred Best with regards to the owner of the stolen bearer bonds, Theodore P Swift. Swift has travelled to London and is staying with Susan, and works to dissolve Obsidian to make way for his expanding business. Reid's investigation falls flat as Best is on the run, hiding from Swift's men with the help of Jackson, and also that Reid has not found the bearer bonds that caused the Train Wreck, despite searching Susan's home with Swift present. Jackson meanwhile confronts Susan about her shooting Reid, proven by her fingerprint, but is convinced to keep it secret as Susan carries his child. Best absconds, but not before telling Mimi about his relationship with Susan. Mimi leaves Jackson, who follows her to the theatre where Rose is performing. Rose, having comforted Mimi and heard of Best's secret hiding, tells Drake. Whilst Jackson is away, Drake breaks into his surgery and finds his bag containing the gun, proof of Susan's guilt and the micro-pictures given to Fred Best by Ackerman. He confronts Jackson about this, leading to a fight. Reid finds them handcuffed together on the pavement, and reminds them of their duties. Best is captured and tortured by Swift, who reveals that he is shipping British Maxim Machine Guns to enemies of the British in a hope to destabilise the Empire (as shown by the Micro-pictures acquired by Jackson). Swift demands to know to whom Best has revealed what he knows, and Susan pleads with Best to comply. Best, however, refuses to betray Reid's company and mocks Swift, angering him. In a fit of rage, Swift loads one of the Maxim Guns, and shoots Best multiple times. With Best on the mortuary table, Jackson reveals all to Reid. Reid, Drake and Jackson piece together the chain of events, and Reid finally finds out that it was Susan who shot him, not Capshaw. Knowing the only way to arrest Swift would be with an informant, Reid heads to Susan's home. Susan, meanwhile, gives the Bearer Bonds to Dr Frayn, as well as the deeds to the Obsidian Clinic. She also passes the rights to Obsidian's land to Jane Cobden, to prevent her father from seizing the land by right. Reid meets her as she is to leave, and reveals that the entire chain of events leading to his shooting, including the events with Horace Buckley and the return of his daughter, were caused by her bidding Capshaw to rob the train of Swift's Bearer Bonds. Revealing that he knows she shot him, Reid promises to spare her instant arrest should she help him bring down Swift. At the abandoned work site that Swift seized from Obsidian, Swift meets with Susan. Reid steps from the rubble, and Swift orders for him to be killed. Jackson and Drake emerge with a pistol and rifle, and kill Swift's men. Swift is then led to the destroyed home of the Buckley's, down into the cellar where Matilda was kept. He is locked inside, knowing that no-one will pass the site to hear him as he slowly dies. Susan gives him a knife, instructing him to "aim for the heart" should he have the courage to kill himself. At H Division, Reid decides it is time to retire, and leaves the station for the last time. Drake assumes the position as head of the Division- where first he must decide whether Susan should hang for the theft of the Bearer Bonds, the Train Wreck Disaster and the shooting of Reid. During their final moments, Jackson comforts Susan by quoting his marital vows "For better or worse- right?". It is not made clear if she hangs or not. Drake finally marries Rose, becoming Mr and Mrs Drake as overseen by Sergeant Artherton and the boy Drake saved from the Train Disaster. In the final scene, Inspector Reid has retired to Margate with Matilda, and they run together along the beach. Reid's obituary, penned by Best and found when Reid found his office ransacked, reads in the voice of Best. As Reid and Matilda hold each other and smile, we hear Best's final message for Reid;
"If there is justice where he now walks, it might be that the care which he wore so heavily, will be lifted from him. Those who knew him, those who did not, those who may have only seen him stride past in pursuit of whatever villainy beset him that day; they might offer a prayer for him. And this might be our prayer, for peace; For his peace.
We, the children of the East, of the Docksides, Highways, Rookeries and Laneways, we pray for the peace of Edmund Reid."