S12, E20: When a young girl is found dead with a doll that is believed to have been left as a totem, detectives Benson (Mariska Hargitay) and Stabler (Christopher Meloni) team up with Captain Jackson (Guest Star Jeremy Irons), a psychologist who assisted them with a recent case, to investigate her murder. Jackson joins the detectives as they retrace the girls last steps and go to meet with her piano teacher June Frye (guest star Elizabeth Mitchell). Jacksons skills prove to be invaluable in deciphering the meaning of the totem and ultimately finding her killer.