While serving in Vietnam, American soldier Nick Parker was blinded by a mortar explosion. Rescued by local villagers, he recovered his health and, though he remains blind, was trained to master his other senses and be an expert swordsman.
20 Years later, having returned to the United States, he visits old army buddy Frank Deveraux, only to find that Deveraux is missing. Parker meets Frank’s son Billy and his mother Lynn, Frank’s ex-wife. Minutes later, Frank’s evil boss, Claude MacCready’s henchman Slag arrives with two corrupt police officers to kidnap Billy to use as leverage over Frank. Nick stops them; the officers are killed, Billy is knocked unconscious, but Slag mortally wounds Billy’s mom before he escapes. With her last words, Lynn tells Nick to take Billy to his father in Reno, Nevada.
At a rest stop on the way to Reno, Parker tells Billy about his mother’s death. Billy runs away from Nick and is grabbed by Slag and some henchmen. Slag escapes as Nick rescues Billy a second time, and Billy and Nick (now called Uncle Nick) become fond of one another.
They reach Reno and find Frank’s girlfriend Annie, who agrees to take them to Frank. After escaping yet another attempted kidnapping by MacCready’s men, Annie suggests they hide out at the home of her friend Colleen. Annie takes Nick to MacCready’s casino, where Frank is making MacCready’s drugs. Annie returns to Colleen’s to watch over Billy while Nick saves Frank. Nick and Frank are reunited; Frank takes the key ingredient in MacCready’s drugs and destroys the lab. Avoiding casino security, Nick and Frank escape and head to Colleen’s to reunite Billy with his dad; they find Colleen dead, Billy and Annie kidnapped, and a note instructing them to bring the drugs to MacCready’s mountain penthouse in exchange for Billy and Annie.
Knowing it is an ambush, Nick and Frank arm themselves with homemade napalm bombs. After killing all of MacCready’s men, they find MacCready holding Billy and Annie at gunpoint. MacCready hired a Japanese assassin to kill Nick, but after an epic swordfight between the two, Nick wins by electrocuting the assassin in a hot tub. Slag shoots Nick in the shoulder and Nick throws his sword at Slag, impaling him. MacCready then tries to interfere only to be stopped by Frank. Billy escapes his rope and throws Nick’s sword to him, but it lands in the hot tub. As Slag reaches for his gun, Nick grabs hold of the assassin’s sword and slashes him, cutting him in half and causing him to fall out of a window.
Frank is reunited with Billy and Annie, and they leave for San Francisco. Nick drops his ticket, choosing not to go; Billy follows Nick, telling him that he needs him. Nick says that while he is fond of Billy, he should go back to his father. Nick crosses the street and vanish as a bus pass him. Saddened by Nick’s departure, Billy throws a toy dinosaur off the bridge where Nick catch it. Billy calls out to Nick one last time and tells him that he’ll miss him. As Frank catch up to Billy, they embrace. Nick smiles or sheds a tear, puts on his sunglasses, while holding Billy’s toy dinosaur with left arm in a sling, and walks off into the distance.