The agents are called in to investigate the murder of a convict who served nine years for rape and murder, but was recently released on DNA evidence.
The police call in Holmes and Watson to consult on a homicide heard by a cutting-edge gunshot detection system when they can't find any tangible evidence that a crime was committed.
Frank hopes to put a four-year-old case to bed as he pushes to find evidence against a suspected cop killer who shot one of Henry's friends.
Detective Rush investigates when a reunion of women who worked together during WWII puts a 1943 death back under the microscope.
Evidence points to an angry ex-boyfriend when a cocktail waitress is murdered outside a popular nightspot. The case hits home for Stabler, who sympathises with the victim's grief-stricken father.