On Amity Island a young woman disappears after a late-night skinny dip. When her partial body washes up on shore the next morning, Police Chief Martin Brody is certain it's a shark attack and orders the beaches closed. Concerned more about the town's economy than public safety, the medical examiner and mayor pass it off as a ‘boating accident, ' and the beaches are reopened 24 hours later. The mayor insists they remain open for the busy and lucrative 4th of July weekend. When a young boy becomes the second victim, his grieving mother offers a reward to whoever catches and kills the shark. Pandemonium erupts when everyone with a boat frantically hunts the shark for the reward. Chief Brody calls in oceanographer, Matt Hooper who examines the remains of the first victim and surmises she was killed by a large shark. "This was not a boating accident!" Meanwhile, several bounty hunters catch a tiger shark. Town officials are satisfied this is the killer, but Hooper is skeptical. He and Brody cut it open to look for human remains. Finding none, they realise the killer is still out there. At night, Hooper and Brody go out on Hooper's boat to search for the shark. They find the half-submerged vessel of a local fisherman. Hooper scuba dives to investigate the wreckage and removes a large great white shark tooth embedded in the hull. A severed human head pops out of the wrecked hull, and a startled Hooper drops the tooth. The mayor discredits their story and keeps the beaches open for the 4th of July. At the beach, Brody's son barely escapes being attacked and another man is killed. Quint, an Ahab-type local character, offers to kill the shark for $15,000. The mayor, finally convinced there's a shark problem, agrees to hire him.
Revealing mistake: When the shark bursts through the window of the cabin, in each of the shots facing Brody, including when he shoves the air tank into the shark's mouth, the glistening water is visible in the window's reflection behind Brody. The shark's reflection is never seen behind Brody, despite the shark's massive size in the small cabin. Bruce must have had the day off during Roy Scheider's takes. (01:58:00)Super Grover