London, 1851. The London to Birmingham mail train is robbed and derailed, injuring the driver and others aboard. With the opening of the Great Exhibition at hand, interest is mounting in the engineering triumphs of the railways, but not everyone feels like celebrating. Planned with military precision, this crime challenges the new Police Force to its limits and leads Detective Inspector Robert Colbeck to discover a tangled web of murder, blackmail and destruction.

As the momentum gains pace, Colbeck closes in on the criminal masterminds. But just as the police begin to think the villains are within their grasp, events take an unexpected turn - Madeleine Andrews, the beautiful daughter of the injured train driver, becomes an unwilling pawn in the criminals' game. In a final race against time, good and evil, new and old, are pitted against each other. But will the long arm of the law be quick enough?