As the Thanksgiving episode began, the gang was playing football in the park at the Honolulu Zoo when McGarrett got interrupted with a call from Mary. She had forgotten to put the turkey in cold water, and it was still unthawed. While the two were talking, there was a knock on the door. It was McGarrett’s Aunt Deb, his father’s sister (played by Carol Burnett), visiting for Thanksgiving. (Deb had been a famous nightclub singer before she had to give up her career to raise Mary). The reunion was short-lived for McGarrett, who got a call and had to leave. A four-man crew at sea had made a gruesome discovery – a body in a barrel.
Meanwhile, Deb and Mary went turkey-hunting but only found a very small bird. And, Chin spoke via skype with Kono, who was in Tokyo, about t leave for Seattle, still in search of Adam. Chin told Kono that, upon their return to Hawaii from Tokyo and the capture of Sato, Five-0 had also captured Michael’s remaining allies. Kono and Adam were no longer targets.
Back at HQ, Chin told McGarrett that Fong had found the barrel with the body to be full of lye, which made for cheap corrosion. Max’s autopsy and the finding of a medical alert bracelet had also identified the victim as Kyle Russo, a Secret Service Agent. McGarrett took Catherine to the head of the Secret Service, who was on the Island, and told him of his agent’s death. McGarrett and Catherine then discovered Russo’s cell phone, which was missing, contained intel on the President, who was on his way to Hawaii.
The team re-traced Russo’s known steps and discovered he was staying in Kailua when he got suspicious of a neighbor named Keith Nolan. Upon a visit to Nolan’s rental, a neighbor told Danny and McGarrett that she had seen Russo and Nolan together.
As McGarrett and Danny were returning to Five-0, McGarrett got a call that told him his Aunt Deb had been arrested. When he went to the jail to find out what happened, she told him she was trying to score some grass from a Narc. She ended up telling McGarrett she needed the grass for medicinal purposes, because she had an inoperable brain tumor. She was in Hawaii to say goodbye.
Chin managed to track Russo’s movements and saw through video footage that Russo was being followed by Nolan, whose real name was Dante Barkov, an assassin for hire, with no allegiance to anybody. Barkov had probably killed Russo when Russo got onto him. A trip to the head of the Secret Service revealed the President’s real reason for an Island visit – to meet with a small group from North Korea to possibly lead to disarmament or a regime change.
Chin told McGarrett Fong thought Barkov might need help to dispose of the body in the lye. Upon examination of the M.O. and the type of lye that was used, Kono found a connection to Barkov. It was a man named Rafael Moreno, a cleaner for the Albanian Crime Syndicate. The problem was, there was no record of Moreno flying into the Island. When Chin got a call from the TSA, a follow-up to his request to check photos at the airport for a possible fit to an alias, McGarrett told Danny about Deb’s tumor. As the two were talking in McGarrett’s office, Chin came in to reveal that the TSA uncovered Moreno flying in under the name of “Diego Silva.” From a car rental, Chin traced Silva to a rental property. When Diego made a move for a weapon, the Captain shot him. The team searched Silva’s residence and found guns belonging to Barkov, who must also have been staying there. They also found lye. Chin also located a boarding pass for Barkov through an alias. Since Barkov arrived on the Island 12 hours before the Secret Service knew of the President’s plans to come to Hawaii, the President could not have been the target. When McGarrett threatened Silva by holding his face within inches of the lye, Silva broke, telling the team that the target was Andrea, the neighbor’s daughter. Until two months prior, she had been working in Dallas as a dental hygienist. Then, she went off the grid. The team found out she had been a witness to a murder of a high ranking member of the Russian crime family. The FBI wanted to talk to her, but she went in hiding and left town.
In the next scene, Andrea and her mother returned home to find the door open. They fled through the woods next door. Barkov was already in the house and saw them. He gave chase just as McGarrett and company arrived and heard gunfire. They found Andrea and her mother at the beach with Barkov about to take the final shot. Andrea had been shot in the shoulder but was ok.
Everyone returned to McGarrett’s house to celebrate and learned Deb and Mary could not find a large enough turkey. Kamekona offered to make a shrimp casserole, which no one wanted. McGarrett said he had a contingency plan and took everyone to the La Marina Tiki Bar. Before they left home, Deb told McGarrett that she had a talk with Mary, and McGarrett went to comfort his sister. At the Bar, the owner, a friend of John McGarrett, asked Deb to come to the stage and sing. The show ended with everyone around the table, McGarrett hugging his sister, as Aunt Deb sang once more.