The dismembered body of a black boy is found in Central Park, amidst what appears to be Santeria type ritual materials - candles, bowls with blood. Benson (Mariska Hargitay) and Stabler (Christopher Meloni) trace the candles to a Santeria group but the leader says there's no way any of the members would hurt a child. There haven't been any reports of a missing child, but he does have an unusual scar on his abdomen. M.E. Warner (Tamara Tunie), still unable to identify the victim, says that based on tests to the bones, the child has only been in New York about four weeks, and before that was in Nigeria. The Detectives check on all immigrants from Nigeria - no one is unaccounted for. So they surmise the victim is illegal, and also realize the child could have been brought here to be sacrificed, as that is still practiced by some African cultures.

When a strange parasite attaches itself to the internal organs of a dying agent, Agent Dunham rushes to Germany to meet with a prisoner who reveals details of a much larger threat.

Emma discovers that her opponent in a campaign for class president is dying of leukemia.