Bulman and Willis join the new inter-city Detective squad and are involved in tracking down a gang of sophisticated villains who are running an arms-for-sale racket from London.
A routine escort job turns dangerous for Bulman and Willis when they are assigned to bring a villain to London for questioning,and two inter-city Detectives are murdered.
Bulman and Willis find themselves working undercover to track down a gang who are hedging their bets by ensuring that the odds are in their favour during a racehorse meeting at Newmarket.
One of Bulman's criminal contacts is beaten up for no apparent reason. The trail leads Bulman and Willis into the world of counter-espionage, and a circus that chooses the towns in which it plays.
Bulman disguises himself as a tramp hoping to catch the drug smugglers 'Tom Thumb' who works Liverpool docklands. He soon discovers that with a fortune at stake the organisation behind the ring will stop at nothing to protect their interests.
Bulman gets a tip-off from an informer about a hired killer. With Willis and Bennett he tries to find out the connection between the killer and two arms dealers.
