The episode begins with Danny and Steve in the middle of the ocean relaxing and Steve is helping Danny catch his first tuna. They are having a chat and in the middle of the conversation, Danny manages to catch his first tuna. Danny is pleased that Kamekona is going to cook them a great feast. But Steve looks a little worried as he spots something at a distance. At a distance a man is signaling for help. They rush to check on him. When they reach the floating boat, the man tells them that he ran out of gas. Danny throws a rope to him and that man gets on to their boat. He has got blood on his shirt. The man then draws a gun at them and tells them that he needs to borrow their boat.
He then asks them to jump in the water and deflates his old boat and rides away. Steve uses the objects on the small boat to prevent the air from leaking; but it is not going to hold long enough. He then jumps into the water to tow the boat to the shore. Danny is paranoid and he feels that they are going to sink. While swimming Danny notices a shark in the water and warns Steve. Steve gets on to the boat and notices that it was a tiger shark. Well, Danny finds Steve annoying even in the face of death! Steve wonders why Danny hates the ocean so much. Danny tells him that he used to love the ocean a lot until he lost his best friend. Danny tells Steve that his best friends Billy died in the ocean while he was swimming towards Danny to help him. That is why he does not like water.
Just then they notice a yacht at a distance and wave for help. Catherine arrives at the HQ and tells Kono that the two men aren’t back and she is worried as they were supposed to reach three hours ago. Catherine tells Kono that Steve took Danny to a secret spot to help him get his first tuna. Ho arrives stating that since it is his uncle’s boat, they can locate it via GPS. Ho finds it weird; Steve asked Catherine to pick them up at the south shore while the boat is at the north shore. They locate the boat and find the duo’s badges and guns on it. They also find the blood stained shirt. It is strange that they came to the shore and then disappeared. Meanwhile, the duo paddle towards the yacht. The yacht looks abandoned.
They get into it and find a dead body lying inside. It appears that the man was shot three times from a close range. Danny picks up an empty shell lying there and infers that it is the same caliber as the hijacker’s gun. Steve tells him to drop that as this is a crime scene and Danny is tampering the evidence. They decide to take the boat to the shore. But the engines are ceased and the radio isn’t working. So, they are still stranded; but on a nicer boat and of course, with a dead body! At the HQ, Charlie Fong confirms that the blood on the shirt does not belong to Steve or Danny. But the prints on the boat match with a man named Gill Scates. He has no priors. He worked as security guard for the safe house, but was terminated for improper conduct.
On the boat, Danny tells Steve that he checked the victim’s wallet and his name is Al Burgess. Also, he found two bullets in the wall which indicate sloppy shooting. So, they try to picture as to what could have happened and how their boat got hijacked. On the island, Ho, Catherine and Kono go to Gill’s apartment. But they don’t find anyone. They find a lot of written material on yachts. They infer that Gill was trying to steal a boat. Then why steal Ho’s uncle’s boat as it is a step down; all the research materials point out to the fact that he was eyeing an expensive one. In the yacht, Steve is still struggling with the engines and the coast guards arrive. They arrest our duo as they are unable to produce their badges.
On finding the dead body, they cuff the duo. Moments later, they verify the duo’s credentials and apologize for their mistake. They say that the man’s wife called as she was worried that her husband hadn’t returned. That is how they arrived at the scene. They are going to hand over the investigation to five-o once they are on the island. The team is happy to see the two of them safe and sound. Steve tells Max that they have preserved the crime scene. Steve is informed that Gill was going through a lot of operative manuals on yachts. They then show them Gill’s pic and they confirm that he was the boat-jacker. Steve asks Ho about the connection between Gill and Al. he tells him that Kono is at Al’s place asking his wife the very same question.
Kono arrives at Al’s residence and meets Katie, his wife and Jenny, his sister. Katie thinks that all this is her fault as she is the one who wanted him to sell the yacht. Actually, Al did not even know how to swim. Jenny states that Al did not even want to buy the boat. Kono shows Katie Gill’s picture and tells her that Gill was on the boat with Al. Katie is surprised and says that it isn’t possible as he worked as a security guard in the neighborhood and they have had some problems with him. She continues to say that he made some inappropriate advances towards her when Al was away. Al got him fired. Kono wonders why Al would take him on his boat after he had Gill fired. At the HQ, Steve tells Ho that Al did not know what Gill looked like as he was away with business when all this happened.
So, it could be possible that Gill wasn’t planning to steal the boat; he wanted to kill Al. so he poses as a potential buyer as he saw one of A’s ads and Al takes him to the ocean and Gill shot. He couldn’t get away with the boat as it wasn’t working and so he hijacked their boat. He planned to get away with a murder and so he would definitely try to blend in. Ho and Kono stake out Gill’s apartment. They get into an argument and Kono gets out getting some coffee. Gill passes and Ho follows him which leads to a chase. They run to the building’s roof and Gill manages to throw Ho off the roof.
Kono arrives and sees that something is wrong and she follows the trail. Just then she finds Ho hanging from the roof. She runs up to help him. Just then she sees Gill running down and she tackles him and cuffs him to a rod. She then manages to pull Ho back to safety. Next, Steve and Danny are interrogating Gill. Gill tells them that he didn’t kill him. Ho tells Kono that the boat was intentionally damaged which would go unnoticed until they were miles into the ocean. Looks like someone set him up; his wife, Katie, as she was the only one who had access to the boat. Kono interrupts the interrogation and tells the duo that Gill and Katie were in on it together.
It looks like Al was about to divorce his wife and she wasn’t going to get anything as per the pre-nup. So, she stood to inherit Al’s millions after his death, minus whatever she agreed to pay Gill. Steve and Danny go back to Gill and tell him that he was being set up by Katie. He doesn’t believe it. So, he calls Katie telling her that the cops are asking him a lot of questions. He tells her that he is going to turn himself in. she tells him that he will be fine as long as he hasn’t left any evidence behind.
She asks him to stick to the plan and never call her again. Jenny overhears this conversation. Five-O arrives at Al’s residence and Jenny walks out with a gun. She then drops her weapon and is taken into custody. They go in and find Katie lying on the floor; dead. Next, the team is at Kamekona’s restaurant where he cooks them a meal from the tuna that Danny caught. The team then drinks to Danny’s first fish. The episode ends.