When a young man is found poisoned in a hotel room, the most peculiar item of evidence is the single fruit gum on the floor. Then a second body is discovered - also in a hotel room, poisoned, and with a fruit gum found nearby - and the police realise they are dealing with a serial killer. Meanwhile, a jewellery robber is operating in Bromersley: staking out dances, plunging the halls into darkness, then snipping valuable necklaces from women's throats. Whilst tackling the riddle of the fruit gums, Inspector Angel and his team must also set a trap to catch a thief ...