While scuba-diving near shipwrecks off Bermuda, vacationing couple David Sanders and Gail Berke recover small artifacts, including a glass ampoule with amber-coloured liquid and also a gold medallion bearing a woman's image and the letters "S.C.O.P.N."

The ampoule contains medicinal morphine from the Goliath, a ship that sank during World War II with a cargo of munitions and medical supplies.

Treece concludes that a recent storm has exposed the morphine and unearthed a much older wreck containing Spanish treasure that is beneath Goliath.

When Cloche's men arrive and dump bait into the water to attract sharks, Coffin tells Treece he probably fell asleep without noticing they were in trouble.

Through research in Treece's library, the trio reconstruct the lost treasure ship's history and locate a list of valuable items, including a gold pinecone filled with pearls with the letters "EF" engraved on it.

Shaw's character Romer Treece was largely inspired by Bermudian explorer Teddy Tucker[4] who makes a cameo appearance as the Harbor Master early in The Deep.

[5][6] The original concept was developed from the story of a Bermuda shipwreck, the Constellation, which sank in 1942, carrying ampoules of morphine among other war cargoes, such as concrete and pharmaceuticals.

[7] Constellation sank after possibly striking the wreckage of American Civil War blockade runner Montana, which Peter Benchley described as having sunk one on top of the other.

Benchley's screenplay was rewritten by Tracy Keenan Wynn and Tom Mankiewicz, while Robert Shaw and Nick Nolte rewrote much of their dialogue.

[9] The production was responsible for a number of technical firsts, including Al Giddings' Petermar camera system and the use of specially modified 5000-watt "Senior" luminaires to provide cinematic lighting underwater.

[14] Upon its release, the film was noted for its opening scene of Jacqueline Bisset swimming underwater while wearing only a thin, white T-shirt and a black bikini bottom.

A possibly opportunistic photo of Bisset in character taken underwater by the wreck of RMS Rhone was used to target the men's lifestyle market without her approval.

[14] Producer Peter Guber claimed this helped make the film a box office success, and said "That T-shirt made me a rich man!

[23][3] Vincent Canby of The New York Times gave the film a negative review, stating that "The story, as well as Peter Yates's direction of it, is juvenile without being in any attractive way innocent, but the underwater sequences are nice enough, alternately beautiful and chilling.