[1] In 1970, former Navy SEAL John Kelly, who recently lost his pregnant wife, Patricia, in a car accident, picks up a hitchhiker named Pam on his way to his home on Battery Island in the Chesapeake Bay.

They quickly become lovers, and over time Kelly discovers her full name, Pamela Madden, and that she is a runaway who became a drug mule and prostitute; she has recently escaped from her drug-dealer/pimp Henry Tucker.

In Vietnam, a U.S. target drone (specified in the book as a buffalo hunter) discovers Air Force Colonel Robin Zacharias as a prisoner of war in a secret camp administered by the NVA.

Since Zacharias possesses highly classified knowledge and has been declared killed in action, Admiral Dutch Maxwell arranges a secret rescue mission for him as well as other American POWs held in the camp.

He later obtains more information on the drug ring from brutally torturing one of Pam's pimps, William Grayson, using a pressure chamber designed to simulate deep-water diving conditions; he is then left to die from severe decompression sickness.

However, his specialized tactics, including advanced close-quarters combat, camouflaging himself as a homeless man, meticulous intelligence gathering, and manufacturing of suppressors for his firearms draw the attention of local investigators, particularly Emmet Ryan, who investigated Kelly's initial altercation and Pam's subsequent death.

However, Kelly manages to capture Grishanov while escaping from the camp, who is then used as leverage to negotiate the transfer of Colonel Zacharias and his fellow prisoners to the Hanoi Hilton, where they will be confirmed as alive and eventually returned.

He bargains with the detective for one more hour of liberty before being arrested; Ryan agrees, but Kelly fakes his death by capsizing his boat.

Without Remorse is said to be inspired by David Morrell's novel First Blood (1972) as well a string of action films that feature violent and "psycho" Vietnam veterans of the 1980s.

Dallas Morning News hailed it as "Mr. Clancy's best", while the San Diego Union-Tribune praised it as "a non-stop emotional roller coaster".

[5] However, Kirkus Reviews gave it a mixed verdict, stating that it is "twice as long as the two rather creaky storylines can bear, but the millions of midlevel, desk-bound, action-loving bureaucrats whose adventurous wishes Clancy so faithfully fulfills are unlikely to complain.

"[6] Publishers Weekly also gave it a mixed review, bemoaning Clancy's "attempts to rationalize this amoral crusade with passages of introspection by characters who are either noble warriors or human scum" as well as "failings of style and moral judgment"; however, they agree that "this overlong, often melodramatic novel seems destined to follow its predecessors to the top of the bestseller lists.

[11] Tom Hardy was approached by Paramount to play Clark, and Kevin Costner was slated to reprise his role as mentor William Harper from another Clancy-based film, Jack Ryan: Shadow Recruit (2014), but this version was scrapped.