The Mechanic is a movie in which Bronson plays a hitman, or mechanic, who worked for a rich man. In the course of visiting this gentleman, Bronson was intrigued by his son's rebellious disapproval for his father's illegal practices. When the father dies, Bronson is caring for the young man immediately afterward. When they return from the funeral, of which neither paid any reverence, they come back to the orphan's mansion to find a huge party of acquantinces of his celebrating his newly-acquired estate. The two leave to go to his lady friends house who threatened suicide. She is sitting down with razors when they arrive, and she repeatedly threatens to kill herself, to which the young man calmly replies, "Alright". Bronson knows it will take about two and a half hours for a woman of her weight to die from the cuts. So when she finally slits them, Bronson and the young man just hang out for an hour at which time she realizes they're not going to help her. She bloodily drives herself to the hospital then as the two still just chill out. They go back to Bronson's nice house in the woods, and the kid finally asks what Bronson does for a living. Bronson reveals that he's "The Mechanic" his father used to speak to him about. Bronson then offers to teach the kid everything he knows in order to become partners, and the young man accepts.

Now Bronson teaches him to shoot and some karate. He is seen quizzing his new partner on drop distances at certain lengths for each type of gun, and he's learning quickly. Bronson then receives a postage envelope which is a new assignment, and he get's the kid in on it. They're assigned to kill three motorcycle-riding, drug-dealing thugs. They arrive at their house with the young kid dressed in a chicken delivery service suit. When the guard comes out, Bronson smacks him good, and they enter the house. The two kill two of the targets, but the third gets out and rides away on a motorcycle. Luckily the two had planned ahead and had a motorcycle in the back of the truck, so Bronson chases him for a while, causing a car wreck and going out of his way to gratuitiously destroying an outdoor, high class party on the way, and of course knocking two people in the pool. When the target finally rides off a cliff, the chase ends.

Bronson and the kid are discussing what went wrong back at Bronson's house when Bronson gets a call. One of his bosses flies him out to talk. The boss tells how his associates aren't comfortable with the idea of this kid being in on the work. Bronson seems to convince him that an assassin trained by himself would be valueable to the organization. The man tries to side with Bronson rather than his associates point of view and suggests that if the next killing is more clean than the last they might reconsider their opinion. With that, Bronson returns home and upon entering calls for his apprentice. The kid isn't around, but Bronson sees in a barely open drawer a folder like the kind they receive target's information in. He sees a picture of himself inside along with his habits and destinguishing characteristics. Now he knows what's up, but he keeps his new knowledge secret.

Bronson next gets a package detailing a job in Naples, so the two live the high life over there for a while, researching their victims. Bronson takes an unbelievable amount of pictures while he's spying. They decide they'll make the kill when the victims are out on their boat. The kid researches the coast line water depths so they can both dive out there and make the kill. They blow up the boat after a small confrontation and return to land. They were spotted by a militant group of people who probably worked for the victim. Anyway this leads to a car chase very reminiscent of the end of Cold Sweat. They end up killing all the pursueing men, and return to their hotel.

When they return after killing a man on his boat, the really awesome part begins. The two toast a job well done, and as Bronson starts feeling sick, the nieve young man laughs at his "triumph." He describes how he put some sort of chemical on the lip of Bronson's glass, and when he poured the champaigne, it moistened the poison and Bronson ingested it. Bronson falls to the floor and it's assumed that he died, although I like to think he somehow prevailed. (More on this!)

It would seem this would be the end of the movie, but the kid goes back in a taxi and chills at Bronson's house and walks around for a while. He then goes out to his beloved muscle car, and, sees a note on the rear-view mirror. Bronson's voice narrates, "Kid if you're reading this, I didn't make it back, and you just tripped a thirteen second timer. Boom-you're dead!" The car explodes, and Bronson is vindicated.