Several of the spectators are killed or injured, either by the sniper or the resulting stampede out of the stadium. Among the spectators, Steve and Stu are killed, and Peggy is wounded. The SWAT team shoots the sniper, but he dies before he can reveal his motive behind the shooting.
The Los Angeles Memorial Coliseum is the site of the pro football championship game between Baltimore and Los Angeles. An unknown sniper has positioned himself atop the scoreboard, and is seen picking out potential targets through the scope on his high-powered rifle. There are several VIPs in the crowd, and the President of the United States is in route, but running late. There are also approximately 100,000 spectators at the stadium.
During the movie, we are introduced to some of the spectators. They include Steve and Janet (David Janssen and Gena Rowlands), a bickering middle-aged couple; Stu Sandman (Jack Klugman), a gambler who is in debt to the mob and needs an LA victory to save his life; Mike and Peggy Ramsay (Beau Bridges and Pamela Bellwood), a financially struggling couple; and Al (David Groh), a swinging single man who constantly flirts with Lucy (Marilyn Hassett), a woman sitting next to him who is being ignored by her date.
The cameraman on the Goodyear blimp first notices the sniper at the beginning of the third quarter, and the television crew notifies the head of stadium security, who in turn calls the LAPD. Police Captain Peter Holly (Charlton Heston), along with SWAT leader Sergeant Chris Button (John Cassavetes) arrive at the stadium and devise a plan to capture the sniper before he begins shooting. They believe that the President is the target, so they notify the Secret Service and has the President turn around before he can arrive at the stadium. One by one, the VIPs are escorted out the stadium while the SWAT team sets up in the light stands and above the press
box. Once they are in place, Capt. Holly tells Sgt. Button that SWAT can go after the shooter once the two minute warning whistle has blown.
As the game approaches the two minute warning, we go back to the spectators. Steve and Janet, who had a fight during the game, reconcile and decide to run off to Las Vegas after the game and finally get married. Stu believes that his life is saved when Los Angeles scores a late touchdown to take the lead in the game. Mike, who apparently is the only person in the stadium who has noticed the sniper, goes to the police to tell them about the sniper, but they think he might be an accomplice and arrest him. Al and Lucy have hit it off, and they will go on a date after the game.
Once the two minute warning whistle has blown, the SWAT team moves in on the scoreboard and the police sharpshooters take aim at the sniper. When the sniper realizes that he is about to be captured or killed, he begins firing into the crowd. Several spectators and SWAT team members are shot and killed, including Steve and Stu. Peggy and Sgt. Button are also shot, but they survive. The sounds of gunfire causes a massive stampede in which the spectators run out the gates or onto the field. Several more spectators are killed, either by being trampled or falling to their death when they jump from the top of the stadium or are pushed off of the escalators. As for the spectators we've been following: Janet is devastated by the death of her now-fiance, Mike escapes police custody and finds Peggy as she is loaded onto an ambulance, and Al and Lucy find each other in the crowd and decide to still have that date.
Eventually, the sniper is shot by the SWAT team and arrested. Searching his wallet, they identify him as Carl Cook, and is immediately questioned by Capt. Holly. However, Cook dies from his wounds before he can answer them, and his motives behind the shooting will remain a mystery.
Tracey adds this important update:
In the TV version the following storyline was re-shot and greatly expanded as the original was deemed to violent.
The sniper is a decoy to distract the police and create a diversion for an art heist at a museum across from the football stadium. The crooks plan to escape when the crowd panics into the streets but they underestimate the amount of panic and the crowd actually prevents their getaway and aids in their capture by nearby policemen.