Alicia awakens in her bed to find another body with a chess piece in his mouth beside her. The team hunts for a cartel boss whose soldiers are gunning for a member of the team. Kono reconnects with Rosie.

When the bodies of two serial killers are found on Five-0 property with chess pieces in their mouths, McGarrett and the team hunt for a vigilante as fear grows that tourists aren't safe in Hawaii.

After a shooting at a nightclub, it appears that the FBI may have ignored previous threats from a local white supremacist group. Also, Kristen wrestles with her commitment to the Bureau and her responsibility to her community.

Newly tested DNA evidence leads to the exoneration of a prisoner who served 16 years for a rape conviction. However, he's investigated again one day later in the wake of a shocking new crime.

A young boy is found wandering alone in Central Park and the search for his parents leads to startling evidence of a planned mass casualty event in the city. As the SVU works with the joint-terrorism task force to find the suspects and the motive, Lt. Benson must also convince Barba to address allegations of rape and torture the boy's mother discloses.

A dangerous warehouse fire puts truck and squad at risk. Tensions are high for Dawson and Casey when Dawson's father overstays his welcome at their home. Meanwhile, Casey continues to fight for his first responders bill, Mouch makes a serious decision regarding his future and Herrmann goes to tremendous lengths to make a young boy smile.