There is a major shake-up in the Flying Squad when Detective Inspector Jack Regan's chief, Jupp, is convicted of corruption. Regan finds himself unable to testify in his guv'nor's defence. But before he is imprisoned, Jupp leaves Regan a last legacy: the files on a tough, ruthless gang who specialise in bank robberies. All that they leave behind is a trail of dead bodies, wrecked cars and bundles of banknotes - apparently abandoned in the haste of the getaway.