Sledge Hammer is a no-nonsense cop whose best friend is his .44 Magnum, and who just loves to use excessive force to collar criminals. In the opener, the mayor's daughter is kidnapped, and Hammer vows to bring her back -- "dead or alive."
After a mobster puts out a “one week only” million-dollar contract on Hammer, every killer in the city, and some financially strapped cops, tries to claim the prize. After an attempted hit takes place in Capt. Trunk' s office, Hammer is ordered to spend the week in a small "Hamish” village. Hammer proceeds to disrupt the lives of this pacifistic community. By the time the hired gunmen arrive, the formerly peaceful farmers, who Hammer corrupted into the ways of violence, assist him.
An escaped convict wrecks havoc in the city, promising even more destruction unless Hammer agrees to meet him in an old west style showdown. The convict is John Kogan, Hammer's childhood rival as well as former partner in the police department. Kogan is also the only man faster on the draw than Hammer… a fact that Sledge is well aware of.
When Hammer and Dori make a trip to the bank they become involved in an armed robbery. The detectives are taken hostage and the robbers demand a plane to take them to Rio. Dori tries to convince Hammer to let her use her training in terrorist psychology and persuasion before he starts blowing everyone away.
Hammer is asked to straighten out some young hoods that have taken over their high school. He discovers that the gang is working for a local car theft ring. Hammer convinces the teens to put their violent nature to good use by training them to become cops.
Hammer and Dori are assigned to locate a serial killer who is bumping off Elvis impersonators. In order to flush out the killer Hammer attends The Famous School For Elvis Impersonators where all the victims were once students. Complete with sequins and pompadour, Hammer enters an Elvis contest and sings The Battle Hymn of the Republic… setting himself up as bait.
When the press reveals that Capt. Trunk is scheduled to testify against a mob boss, Hammer is assigned as his bodyguard. In an attempt on his life Trunk is wounded and taken to the hospital. Sledge decides to make a bogus report that the captain’s been killed, but an assassin learns Trunk is still alive and infiltrates the tightly secured hospital posing as a physician.
When a group of vigilante cops begin killing criminals who have gotten off due to legal technicalities, Hammer is assigned to infiltrate the group. To test his loyalty the rogues assign him the task of killing a female district attorney who is out to stop them. While this same D.A. tries to seduce Hammer in her home, Sledge learns that she is really the leader of the vigilantes and plans to kill him.
Hammer and Dori pose as a couple wanting to adopt a baby in order to discover who is kidnapping infants from a hospital maternity ward. They learn that the hospital’s head nurse and her brother are behind the abductions, which lead to an incongruous shootout in a baby supply warehouse.
After a winning game show contestant is murdered, Hammer investigates. He learns that the show’s host did the killing, obscuring the fact that he’d also embezzled the prize money. Hammer signs on as a contestant to make the host try to kill again.
Hammer is poisoned by a mysterious woman and learns that he has only twelve hours to live. Hammer learns that the only cure for the poison is held by a group of monks in the Andes who have taken a vow of silence. Severely weakened, Hammer must hunt down the perpetrators before it’s too late… made worse by the fact that it’s also daylight savings time.
Hammer gets to meet his idol, a retired police detective with a reputation for old school toughness, and gets him a job as a security guard at a local jewelry store. When the store is robbed, the old man is wounded and ends up at a retirement home. Hammer feels responsible for what happened and vows to get revenge on the thieves… not realizing he’s also giving the old man one last shot at glory.
When Hammer arrests the leader of a Satanic cult, Internal Affairs insists that the cultist be allowed his one phone call. Soon after the cultist makes the call, the precinct headquarters is surrounded by hundreds of demented devil worshippers. With communications to the outside cut off, Hammer devises a risky plan to lift the state of siege.
A gang of silver thieves, working in cahoots with an unscrupulous police psychiatrist, destroys Hammer's psyche when they steal his beloved 44 Magnum… effectively crippling the crime fighter.
When Hammer's favorite hanging judge dismisses charges against a local mobster, Hammer investigates. The judge is found murdered with the only clue leading to a shady pool hall. Sledge poses as a pool shark to uncover the racketeer who has been blackmailing city officials.
While pursuing a counterfeiter, Doreau gets knocked on the head. The results are a personality disorder that makes her behave in the same anti-social, violent manner as her partner Hammer.
Hammer's search for a jewel thief leads to an upscale beauty salon, where henchmen rob the society matrons’ homes during their hair appointments. Hammer goes undercover as a hairdresser in order to stop the British thieves who are after the ladies' jewels.
Hammer goes on trial for the murder of the city's leading crime boss. Capt. Trunk and Dori are called upon to give damaging testimony against Hammer and everyone is convinced he’s guilty, including Hammer himself.
Bodybuilding terrorists led by a female aerobics instructor steal a nuclear warhead from the military and threaten to destroy the entire country. Hammer and Dori are assigned to the case and are captured by the group. When Hammer gets control of the situation he tries to disarm the device. Seconds later, the bomb explodes.
