Danny moves into the McGarrett house because his house has mold. Philanthropist George Parks gets killed by robbers and his giant koa tree, worth $1 million, gets stolen. Junior finds out his parents' house got robbed. McGarrett sends Junior and Tani to investigate. Junior thinks he knows who did it, his old friend Owen, who used to live with the Reigns and knew about Junior's father's secret hiding place. Grover and Quinn check out Lolo Joe, the island's biggest koa dealer. He said he had been approached by a crew offering a large supply of koa. Grover and Quinn go to the planned buy but find the entire crew dead. One portion of the tree is missing, which had a hollow within it. Tani's brother Koa gives them a lead on the drugs they saw in Owen's mother's apartment. Body parts from a missing Jane Doe may have been inside the koa. Junior and Tani find Owen and he tells them where he pawned what he stole. Junior destroys his drugs. Junior tells him his choices are to be arrested for the robbery or go to rehab. Grover and Quinn confront Preston with the skull from the tree. Preston admits to accidentally killing Lena, a German student. But Grover doesn't believe him. Owen goes to rehab. Junior finds letters from Afghanistan in the box but he didn't write them. Noelani says Lena was murdered, not killed accidentally. Preston is covering for his sister, who killed Lena. Darren shot the robbery crew. Junior's father thanks him for recovering what was stolen. Junior's C.O. had written the letters. Junior and his father make up. He brings his parents to the Thanksgiving meal which Princess prepared. Steve knows Danny moved in to keep an eye on him. Everyone plays football before dinner.