Rachel and the VCTF team search for a serial killer (guest star Greg Kean) who strangles women with knots of their own hair, but when the latest victim proves to be the daughter of powerful mob boss James Perrone (guest star Ray Wise), the FBI profiler must gain the grieving father's confidence to learn more about her habits. Meanwhile, Rachel is under pressure from the Bureau's Organized Crime Division to take advantage of her access to Perrone and wear a wire to trick him into confessing to a fellow mobster's murder, thereby ending a lengthy investigation.

After a police officer and other authority figures are found stabbed in the backs, Rachel centers her investigation on a young woman, Pamela (guest star Marcia Cross), who is reported to have assumed multiple identities which probably spring from memories of early child abuse. But Rachel faces an even greater personal threat from an FBI honcho (guest star Gregory Itzin) who has falsely accused her of forcing a sexual relationship of a subordinate -- a charge that could ruin her career. Elsewhere, Bailey confronts George over his reliance on prescription drugs and orders him to get help.

In the season finale, Rachel is emotionally distraught after her brother's death and she's further rattled by the mind games played by wanted Agent Marks, who she believes is responsible for a series of murders, but Marks needs her to accomplish his own agenda. Malone has even more concerns when he is ordered to conduct a performance review of his VCTF members as rumors fly in Congress that the elite unit will be disbanded.