81861: Jarvis Swarbrick MP, universally admired for his work towards unifying East Anglia's tangle of railway networks, is travelling by train with his wife when he is threatened by an armed robber. Swarbrick defies the man and is promptly shot dead. As the only detective in Britain with enough expertise for the job, Inspector Colbeck is brought in to investigate the tragedy. But as Swarbrick's glowing reputation begins to crumble, the line of investigation isn't clear: is this the act of a bungling burglar, a business rival, a disgruntled son, or a jealous lover? Whoever it is, they are determined to involve Colbeck in their fight. Is the Railway Detective following the right track, or will he need to switch points to bring the murderer to justice?