Sometimes the best way to go about your business is quietly. Lots of businesses advertise but those in the criminal world need to tread more carefully. There's a massive difference between publicity and public attention. Of course, criminals need to advertise their wares as well; how else can they sell them? Stolen goods, re-badged cars, jewellery, counterfeit bank notes, government bonds or drugs of every kind imaginable. The difference between a public company and a crime gang is that while one wants broad brand-awareness, the other wants contact with their customers and only their customers. Proceeds of crime are always a personal transaction; there is never an invoice. In this latest adventure, Harriet McGovern has an even more enthusiastic lease on life and decides to spend her lunch breaks running the streets of London. Mainly her area of South London but occasionally along the river or even across it.

There are many bridges and tunnels traversing the world-famous Thames and Harriet shares these structures with everyone else, including a group of brilliantly coordinated swashbucklers who decide that river crossings are best used to transport ill-gotten gains. Harriet catches wind of their activities and now it is time to act. With the help of her housemate and fellow police officer, Steve Marchant, and their respective partners Jenny and Meredith the chase is on. The real game, though, is to uncover the most frightening type of criminal mastermind; one with the ability to exert patience, discipline and, worst of all, the dark art of logic to his treacherous endeavours.