The Oath is a 1995 horror novel by Christian author Frank E. Peretti. It describes a mining town in the Pacific Northwest (called "Hyde River") and of a mysterious "Oath" which guards a horrible secret, a secret which all the town knows but refuses to acknowledge. The novel, in addition to being horrific, also uses symbolism frequently.
On a dark night, in the middle of the wilderness above Hyde River, a wildlife photographer, Cliff Benson, is brutally killed. His wife, Evelyn, is covered with blood from the attack and is running for her life down the mountainside, where she is found by a trucker and taken to a hospital. After her initial awakening, she has virtually no memories of the attack, save for what she describes as a "big shadow".
Steve Benson, a wildlife biologist and Evelyn's brother-in-law, is immediately on the scene along with Evelyn's parents. Evelyn tells them everything she knows, but can't recall more than the "shadow". As with many other mysterious deaths in the valley, the death is blamed on a rogue bear. However, Tracy Ellis, one of the town's cops, believes Evelyn may have actually murdered Cliff herself.
In the meantime, Harold Bly, the "town boss" and owner of the Hyde River Mining Company, kicks his wife Maggie out of the house because of a betrayal. She begs him to let her stay, but he tells her that "it's over". Distraught, Maggie attempts to convince her neighbors to let her into their houses, all of whom turn her down except for the town mechanic, Levi Cobb.
The next morning Tracy takes Steve to the site of the killing. Tracy tells him that she and Sheriff Lester Collins had visited the site earlier that morning to remove the body. Tracy informs Steve that only half of Cliff's body was found, casting a shadow of a doubt on the bear theory. Later on, when Steve and ranger Marcus shoot down the suspect, the autopsy reveals no human remains, which should have been present.
Steve decides to stay in Hyde River for a while to investigate further, but soon he finds out that he is not wanted. He nearly gets into a big fight at a tavern, and consequently he and Levi have to be escorted out by Tracy Ellis, who walked in just in time to avert the violence. Levi takes them both back to his shop, where Maggie Bly is presently living. Maggie has the windows all shut and boarded for some unknown reason. But whatever it is, she is scared stiff, and it is only by Tracy's gentle coaxing that Maggie manages to tell them that she and Cliff were having an affair. Steve then forms another hypothesis: Harold may have killed Cliff after finding out. However, the evidence does not favor this either.
Maggie leaves the shop with Tracy and stays in a hotel while the mystery is being unravelled. However, she suddenly wanders off one night, and briefly stops at her husband's house to tell him "goodbye". She then goes to Old Town, the section of Hyde River that has been abandoned due to superstitions and fears, where she disappears without a trace.