Maggie Forbes, just promoted to Detective Inspector in the Metropolitan Police, reaches a crossroads in her life. Within hours of her promotion her police constable husband is shot by two brothers. Maggie is ordered to stay at home while her colleagues investigate the killing.
Tired of sitting at home, Maggie disobeys orders and sets out to find her husband's killers. Having received a tip-off from a contact in the criminal world that the gun used in the crime was supplied by illicit arms dealer Jackie Frost, she hands her information to Chief Inspector Russell - and tells him that she is resigning from the force.
Having withdrawn her resignation, Maggie tries to sort out the problems facing Susan Scott and her daughter. What she doesn't know is that trouble is on her own doorstep - her son Steven has taken to drinking.
When a woman is found dead in a 'love nest', Det. Insp. Maggie Forbes is handed the case. She builds up a strong picture of how the crime was carried out, but further investigations lead to several shocks for the people involved.
A young man found murdered in the London Underground one morning has been stabbed with a knife. The nature of the crime points to a homosexual encounter - which eventually leads Maggie to a blazing row with her colleague, DI Croft.
Interviewing an unsuccessful businessman who is suspected of deliberately setting fire to his premises for the insurance, Maggie is unimpressed when the man offers her a bribe. But even stranger offers are waiting around the corner - that Maggie can't ignore.
Maggie investigates the death of Melody, a local prostitute. Yet when she questions some other call girls for an insight into Melody's background, Maggie suspects that their pimp, Miller, has put the "frighteners" on them.