Stabler and Benson are called to the scene of the savage murder of a prostitute. The woman, who had been with a customer, had been brutally gutted and stabbed over forty times before her body was set on fire. Witnesses who saw the killer all say the same thing: he wore a beard and had a crazed look in his eyes. When a hit comes back from the sex offenders' database off the semen that was found with the prostitute, Benson, Stabler, Munch and Fin pick up a paroled rapist known as Fredericks at his construction job. Yet no sooner are Benson and Stabler trying to wrangle a confession out of Fredericks in the interrogation room, than they receive a report that there has been another savage killing--this time of a young woman who worked as a book publicist. Like the hooker, the second victim was also viciously sliced up in the same M.O. Although it still possible that Fredericks might have killed her--the timeline still works out--the DNA evidence at the murder scene rules him out as a suspect. Apparently he was with the hooker shortly before she met the real killer.

The body of the second victim has barely cooled before the killer--who is now known as the Night Ripper by the local media--strikes yet again, and this time it's even more heartbreaking: he kills a father and his young son in the men's room at an arcade. When a third man tries to save the boy's life, the killer stabs him as well, but he'll live. He's able to provide a detailed description of the assault to Munch and Fin. When Benson and Stabler arrive, they encounter a woman who is the mother and wife of the two deceased victims. She stands dazed outside the men's room, her tragic loss not having completely sunken in. A task force, with Cragen in charge, is set up to apprehend this madman before he can kill again. Benson catches a lucky break in the squad room when she spots a suspicious report that had been called in by a deli: somebody paid them with a bloodied check.

Like Countdown, this season's other five star episode, Scourge is also a race against time. But even when the race to capture the killer is finally over, the story is far from it. Just when ADA Alex Cabot, armed with the death penalty, is about to enjoy skewering the defendant in court, Scourge throws a monkey wrench into these proceedings when Dr. Huang makes a startling revelation that actually makes the killer a somewhat sympathetic figure--at the very least, he has an excuse for his bizarre, murderous behavior. The regular cast is great, but the two guest stars are marvelous. Richard Thomas, best known as John Boy from the Waltons, is superb as the Night Ripper. And Karen Allen, best known from her roles in the films Raiders Of The Lost Ark and Starman, is wonderful as Thomas' loving, still-devoted wife. While the balance of the story shifts to helping the defendant by uncovering the truth of what happened to him in the past, Elliot Stabler still receives a final, devastating reminder of the four people whom the killer brutally slaughtered in the very last moment of this episode, which is both painfully poignant and haunting at the same time.