Chin investigated the mysterious murder of a high school classmate on the latest episode of "Hawaii Five-0."

In "Ho'i Hou" (Reunited), Chin (Daniel Dae Kim) and Jerry (Jorge Garcia) go to their high school reunion. While there, one of their high school classmates, Laura Richmond--the heir of a macadamia nut fortune--is murdered.

Kono (Grace Park) and Catherine (Michelle Borth) join Chin and Jerry at the reunion to investigate the murder. They discover that Laura has not returned to Oahu for 25 years, and that she did not correspond with anyone on the island during her time away.

They also discover that an ace of spades card was found on her body, and that she withdrew $200,000 in cash from her trust fund prior to the reunion.

Meanwhile, Danny (Scott Caan) and McGarrett (Alex O'Louglin) are in Cambodia to search for a mysterious grave that the CIA does not want McGarrett to locate. But they do find the grave, and discover that it has been unearthed. The find an empty coffin that contains a few strands of hair, which McGarrett takes to investigate.

Back in Hawaii, Chin gets a call from Kono that the prints found on the card match another classmate, Tony Gibson, who has a criminal record. Chin and McGarrett, who have returned to Hawaii, meet Danny at a hotel, where he is working as a magician.

The team arrests him and takes him back to Five-0. He tells them that he "planted" the cards on a lot of his classmates, and is then cleared when they find out that he accepted a gig at the hotel before Laura was on the island.

Kono then discovers that Laura withdrew cash to pay the hospital bill of someone named Nina Johnson.

Kono and Chin visit Nina, and it turns out she didn't know Laura. But Nina has a son, Korey, who disappeared 25 years ago. They go to Korey's room and see photos of him and Laura. The team believes that Laura and Korey were romantically involved, and that her boyfriend, Alan Kim, found about the affair and killed him.

Chin and Kono goes to Alan's house, only to find that he was beaten and is being taken away on a stretcher.

The team then finds Laura's witness statement in the investigation about Korey's disappearance, and find out that she gave Alan an alibi for the time of Korey's disappearance.

Catherine and Chin then go to the location of the high school reunion and find time capsules that contain film. Jerry develops it and finds a photo of Laura's brother, Bradley, Laura and Alan.

The team returns to the macadamia estate and arrests Bradley, but he insists that Alan killed his sister.

The team goes back to the hospital and arrests Alan, who tells them that he and Bradley only wanted to teach Korey a lesson. He says they beat him up, but he fell and hit his head on a rock, which killed him instantly. Laura was going to confess the whole thing, so he killed her.

Meanwhile, McGarrett goes to the agent's office who is investigating the hair from Cambodia, but finds that the agent's room is swept clean, and the agent is nowhere to be found.

He recieves a phone call from an unnamed person who tells McGarrett that the agent never existed, and neither did the grave in Cambodia. McGarrett says that he will stop at nothing to find out how the grave is connected to his mother.

On the next episode, "Kul l Ka Pili Koko," "After following up on a tip, Steve and Danny are trapped inside an abandoned building that is rigged to explode."

Watch the promo for the next episode below, which airs Friday, April 11 at 9 p.m. EDT on CBS.