The Domino Principle

Roy Tucker is serving a life sentence in San Quentin for the murder of his wife's first husband. Warden Ditcher introduces him to Marvin Tagge, who explains that he represents a secret organization that runs the country from behind the scenes, with Ross Pine as his associate. Tagge offers Tucker an escape and a few weeks of service in exchange for a new life.

Tucker confides in his cellmate Oscar Spiventa, who warns that he is being groomed as an expendable hitman by 'them,' a nameless cabal that runs the country from the shadows. Tucker dismisses Spiventa as paranoid.

But Tucker is drawn by the possibility of reuniting with his wife Ellie and starting a new life. Facing the lure of escape, he ultimately decides to accept the offer.

Arrangements are made for the prison staff to look the other way, and Tucker and Spiventa are driven out the main gate in a bread-delivery truck to a rendezvous point beneath the Golden Gate Bridge.

At the rendezvous, Spiventa is killed by the organization, and Tucker is taken to the Hyatt Regency San Francisco, where he meets General Tom Reser, a confederate of Tagge and Pine.

Tucker is allowed to enjoy the city for a while before being reunited with his wife. News broadcasts reveal Spiventa's body has been found, and authorities believe he killed and escaped to Canada. He also meets with his lawyer Arnold Schnaible, who is later found dead.

Tucker is flown to Puntarenas, Costa Rica, where he is given a bank account with $200,000 and a house to share with Ellie, who believes Tucker has been released pending a new trial.

After a few idyllic days, Tagge, Pine and Reser return the couple to Los Angeles, and Tucker is directed by Reser to practice shooting tin cans from a rifle while riding a helicopter, part of the assassination prep.

The organization kidnaps Ellie, and Tucker reluctantly submits to their demands to protect her. The pressure shows how far Tucker is willing to go to keep her safe.

The next morning, Tucker shoots the target as planned, but the target's security detail damages the helicopter, forcing a crash-landing in the mountains. The helicopter and the pilot are destroyed, ending the escape.

Tucker takes Pine hostage, demanding a plane and the return of Ellie; Tagge complies.

On a plane with Ellie, Tucker realizes he has been manipulated for over a decade. Tagge explains that Spiventa is alive and was recruited in 1961, and that Tucker's life has been built on the domino effect of an order from above.

During the flight, Tucker sees someone planting a toolbox in Tagge's car. Unable to abort takeoff, he watches Tagge be blown up with his car.

The couple returns to Costa Rica, but Tucker's fragile new life collapses as Ellie is killed by a passing truck. Spiventa and Pine arrive, and Tucker shoots them both, throwing their bodies into the ocean.

The film ends with Tucker walking along a beach with a rifle, vowing not to give up, while another assassin remains hidden in the shadows, keeping him under threat.