Mark Tuesday, insurance broker and owner of the Tuesday Agency, is brooding in his office, after hours, about his failing marriage with his wife, Marie, when he receives a phone call from the owner of a large trucking company and new client of the agency, informing him that one of his trucks has crashed, and the driver has been killed. The owner, Ben Wozniak, asks him to go to the scene of the crash and investigate the scene.

At the scene, he discovers there had been two witnesses, one of whom — a man named William Closer — had already left, and a young woman named Elise Young who, he realizes, is his daughter's school teacher. He feels an immediate and disturbing attraction for her and — after examining the scene, and recognizing that the crash occurred under questionable circumstances — persuades her to let him drive her home. But, before leaving with her, he also speaks with two sheriff deputies present at the scene, both of whom appear strange in their behaviour toward him.

On the way back to Glen Park, where he and Elise Young both live, he convinces her to stop for a drink with him at an elegant restaurant called The Sanctuary, where he also knows the owner, Jim Sloan. After introducing her to Jim, and asking him to keep her company, he calls Ben to advise him of what he had observed at the crash site, and is surprised when Ben now suggests that the driver may have been drugged. Dismissing the suggestion as outlandish, he returns to Elise and now suggests they have dinner. She agrees and, during dinner, and afterward on the drive home, he again feels, and resists, a compulsion to tell her about himself — something which he has always managed to avoid in the past, with everyone he has ever known — even his parents and his wife.

He proceeds with the investigation of the fatal accident, which becomes complicated by the disappearance of his wife, and his involvement with Elise. As he uncovers the facts surrounding the driver's death it soon becomes evident that it was not an accident but, rather, the result of the latest in a string of hijackings staged to cover up a drug smuggling operation. The drugs are being smuggled into the country in cases of exotic gourmet foods and distributed by a company whose traffic manager is William Closter, the other witness to the accident. Closter subsequently commits suicide, but it soon becomes evident that his death, too, was murder. Based on information furnished by Mrs. Closter, and a young woman named Wanda, he is able to establish the complicity of those involved in the smuggling/hijacking operation. However, his success in the investigation leads to the death of his wife and the near fatal shooting of himself.

Throughout, he struggles to reconcile the present with the past. Having led a solitary, introspective, and almost totally selfish existence before being drawn into the investigation, he is at first confused and dismayed by the feelings aroused in him by Elise. But, overcoming his initial reluctance, he finds he is able to express to her all the emotion he has kept bottled up within himself since childhood. It also leads to reconciliation with his mother, and a better understanding of the causes of the failure of his marriage to Marie.

But, it is not until a final confrontation with the leader of the smuggling/hijacking operation that he fully understands the real meaning of the quotation from the Rubiyat of Omar Khayyam: "The moving finger writes; and, having writ, moves on; nor, all your Piety nor Wit shall lure it back to cancel half a line, nor all your tears wash out a word of it."