DeFranco wears Tyler's rig to a public restaurant. The assassination appears to go flawlessly, however, when Tyler is picked up by the Department of Justice agent in charge, Lipton (Cliff DeYoung), the agent tries to shoot him. A struggle for his gun ensues and the car crashes, allowing Tyler to escape. Tyler is nearly killed in a phone booth a short time later and retreats to his girlfriend Ellen's (Diane Venora) apartment. In the morning, Ellen is shot by a sniper aiming for Tyler. Tyler kills the sniper when he enters the apartment to finish the job.
A Manhattan homicide detective, Leo McCarthy (Dennehy) becomes interested in the case because he's been pursuing DeFranco for several years. He discovers that the assassination was an illusion and that Tyler planned it.
Using an elaborate phone prank, Tyler brings Lipton out in the open and kidnaps him in his squad car. He stuffs Lipton into the trunk and tortures him for Mason's address, believing that DeFranco is hiding there, waiting to be transported out of the country. Tyler steals back his impounded van and escapes following a furious chase through Lower Manhattan. Tyler goes to Mason's mansion. Using his special effects expertise, he kills several of Mason's guards.
Suspecting that Tyler will kill him next, DeFranco shoots out several windows in Mason's study. Tyler falls through one of the windows, appearing to be dead. DeFranco tries to leave the house when the helicopter arrives but receives an electric shock from the house's security system (which Tyler may have specially rigged). The shock disrupts DeFranco's pacemaker and he dies of heart failure. Before he dies, he gives Mason a key to a Swiss safe deposit box containing all the funds he stole from the Mafia.
Mason prepares to leave and is confronted by Tyler, who points a UZI SMG at him. Mason tries to bribe Tyler with the key he took from DeFranco. Tyler considers the offer and places his gun on a table, hovering over it for a moment. He tells Mason that the plan won't work with the police outside. Mason grabs the gun Tyler had set down. Tyler shows Mason that he has the bullets for the gun and a tube of Krazy Glue, which he used to glue the gun to Mason's hands. He shoves Mason out the front door where he's shot by the police waiting outside. Among them is Leo McCarthy.
Tyler is taken to the morgue, still alive, and jumps out a window. He's immediately found by McCarthy. The film ends with Tyler impersonating DeFranco and retrieving the Mafia funds from the bank in Geneva.
Vincent Canby praised the look of the film in his review for the New York Times, writing, "although the movie, which looks as if it had been made on an A-picture budget, has a lot of the zest one associates with special-effects-filled B-pictures. In his review for the Globe and Mail, Jay Scott wrote, "F/X is simply out to give a good time, which it does superbly. Paul Attanasio praised Brian Dennehy's performance in his review for the Washington Post: "Dennehy brings magic to the role - he's large, and he enlarges it. With his sly eyes and little can opener of a nose, his shoulders a yard wide, his hair massing in gray curls behind his ears, he dances through the movie like a mastodon in toe shoes.