Flippa's drummer is running late for their set at the Hawaiian Cultural Festival. The drummer, Luka Palakiko, is murdered while on the phone with Flippa. He was stabbed nine times. Noelani found a long blonde hair on his body, which belongs to high schooler Annie Kehr. She took a flight after Luka's death. Annie is found and said Luka was helping her as a counselor. She escaped from the conversion therapy in which her parents had placed her. Her parents denied knowing Luka, but they had hired a private investigator to follow him. An ex-con, Connor Russell, was sighted near Luka's murder scene. Jerry and Junior break into his room. When Jerry tries to extract his computer, it explodes. Based on trace evidence on Connor's clothes, McGarrett determines he's built a fertilizer bomb. He stole Luka's van to house it. Grover and McGarrett talk to Connor's former cellmate, Roger Barton. Barton says Connor may have had a psychotic break. Connor has joined up with a Neo-Nazi group. A patrolman checks on Connor looking for the van, and Connor slices his throat. Jerry uses an algorithm from the FBI to figure out who wrote Connor's manifesto. It matches up with text written by Barton. After Grover and McGarrett try to force information out of Barton, a burner was found in his cell. A red van is found on the side of the road, with the driver tied up inside. Connor took his van instead. Jerry locates Connor's video on a chat room. His target is a community center. Jerry finds Connor's van. McGarrett wrestles with Connor, then Grover shoots Connor. The bomb squad defuses the bomb. At a bar, Grover tells McGarrett about how,, years ago, two rednecks were saying hateful things at a diner in rural Illinois. Grover got beaten up after he confronted them.