The search for a young boy's parents after he is found alone in Central Park leads to the possibility of a planned mass-casualty event in the city; SVU works with the joint-terrorism task force to locate the suspects.
When a girl is attacked, a young man is arrested. They later learn that he takes steroids which is what made him attack her. The guy turns out to be the son of a cop Stabler knows. The cop later attacks his son and it turns out he is also taking steroids. Stabler is forced to deal with issues involving his own father.
After the bones of a boy who disappeared in 1978 are found at a playground, a recovering Stabler teams up with Vizcarrando to determine the boy's identity, which leads them to a cold case involving four missing Puerto Rican boys whom were never found.
A hooker is alerted by noise from the neighboring hotel room, and finds there a badly manhandled girl, who later has a miscarriage. Then the girl's father shows up and the case starts getting more complicated every time the cops learn something new about it.
When a teenager and her younger sister end up in the hospital after a day at the park, detectives learn that both girls were abducted from New Orleans after Hurricane Katrina along with a third sister who is still missing. Despite the interference of a local reporter, Jackson Zane, detectives are able to catch the kidnapper, a known pedophile, and recover the girl, but when Alvin Dutch dies and the autopsy determines it was Anthrax, Benson puts everything on the line so that she can get the truth out there.
A Hudson University co-ed dependent on financial aid is found murdered with an unexplained influx of cash. Her wealthy roommate is found with one of her rings, making her a suspect as the two were not friends. Benson, Fin, and Stabler have several theories about her murderer and their motive and investigate the various suspects; the roommate, her childhood friend, and someone connected to a heavily trafficked website where the victim was selling term papers for cash.
A band of teenage siblings attack and sodomize a teenage girl, who is a gifted piano student at a prestigious high school in Harlem. When Warner identifies the attackers as overweight, Detective Stabler and his new partner, Detective Lucius Blaine, track down the siblings -- who claim they attacked the victim to avenge an attack on their morbidly obese brother.
In seventh season finale, rock star Derek Lord goes on a national talk show and lectures about the abuse of psychiatric drugs. Meanwhile, an unstable young woman loses her virginity, goes off her prescribed medication, gets behind the wheel of a car, and mows down 10 people. As these events are played out in a highly charged way, the argument about prescribed "meds" is challenged.