At headquarters, the team wonders where Gibbs is. McGee finds that Gibbs' cell phone signal is close by. Gibbs calls Tony and tells him to go to the construction site. At the scene, Kort tells the team that the men killed each other. Tony tells Kort that his story sounds phony. Tony tells Ziva that he doesn't trust Kort because he tried to kill him and he blew up his car (5.01 Bury Your Dead). Later, they see a sedan pull into the construction site. They surprise the man with their guns drawn. Kort wonders who the man is.
At the headquarters, the team learns that Siravo is engaged in criminal activities all over the world. They see that Siravo had a ship named the Borealis. Perry Sterling, the man from the construction site, is brought to the interrogation room. Vance is suspicious of Kort arriving at the end of the gun battle at the construction site. Gibbs meets with Perry in the room. The man tells Gibbs that he is an accountant, that he got lost and entered the construction site to ask for directions. Gibbs asks Perry about Siravo and he admits that he is his accountant. Gibbs asks about the Borealis and Perry says that Siravo doesn't own it. Perry says that he moves Siravo's criminally obtained money into clean businesses. He asks Gibbs for immunity in exchange for his testimony. Vance tells Gibbs that he is going to contact the U.S. Attorney.
Abby tells Ducky that she found shell casings from a caliber that is different than the ones used to kill the men at the construction site. She tells Gibbs that she thinks there was a third shooter.
In the office, Tony tells Kort that he thinks that he is lying to the team. Gibbs and Tony enter the briefing room. Vance shows Tony and Gibbs a video showing the Borealis being blown up by a bomb planted onboard. Gibbs returns to the interrogation room and sees that Perry is taking drugs for his reflux disorder. Gibbs shows Perry the photos of the men that were killed at the construction site. Perry figures that Siravo was closing up shop and wanted him dead. Perry says that he knows how to get ahold of Victor Flores, Siravo's number two. Perry asks Gibbs if he knows Captains of Industry 3. McGee and Abby learn that Captains of Industry 3 is an online game that barely anyone plays. They figure that Perry used the game to communicate with other criminals.
Tony asks Kort why he thinks the men killed each other. Kort says that he thinks that the men had a secret lover suicide pact. Tony asks Kort why he dug up information on Vance. Kort tells him that he didn't have to read Vance's file.
Tony, Perry and Ziva go to the safe house. Perry looks around and says that he doesn't like his surroundings. Perry says that he is hungry and tells Tony that he is on a macrobiotic diet.
McGee and Abby create avatars and play Captains of Industry 3. They figure that Perry and Flores use codes to communicate. They receive a message from Flores and learn that he wants to meet Perry at the park. Gibbs and Kort leave to meet Flores.
Back at the safe house, Ziva tells Perry that she can't believe that he never had a girlfriend. Perry says that he thought that making lots of money would help him meet women. Tony returns to the safe house with food. Perry tells Tony that he is out of pills and that he needs to take one with every meal.
Gibbs and Kort find Flores' car at the park. They discover Flores' dead body and another man who was also shot and killed. Later, the team goes to the scene to investigate. Ducky and Jimmy say that the men where killed less than two hours ago. Gibbs and Kort figure that the men killed each other. McGee tells Gibbs that both men worked for Siravo. Later, Gibbs updates Vance about the case. Vance tells Gibbs that Kort was suspended by the CIA. Vance tells Gibbs that he knows that Kort gave him his file. Vance tells Gibbs to find out what Kort wants in exchange for helping him.
Back at the safe house, Tony tells Perry that he will get his immunity as soon as he talks to the U.S. Attorney and passes a polygraph. Tony tells Perry that he is going to spend the rest of his life moving from safe house to safe house.
Ducky and Jimmy talk about barbershop music. Jimmy says that he used to be a tenor in college. Ducky says that the unique characteristic about barbershop music is the fifth note, the sound that is made when the voices combine. Ducky says that they are missing the fifth note from the quartet of dead bodies that they found. Gibbs walks in and tells Ducky that he found horse manure on all of the dead men. Ducky tells Gibbs that he thinks that Siravo is staying at a place where there is horse manure.
Ziva walks down the street and sees two men walk toward Perry's safe house. Ziva calls Tony and tells him about the ambush. Ziva enters the safe house and shoots both men as they break into the apartment. Later, U.S. Marshalls arrive and take custody of Perry.
Abby tells McGee that she thinks that there is a leak. Gibbs arrives at the lab and show Abby and McGee the GPS log from Flores' car. Gibbs sees that the car stopped at a horse ranch. They figure that the ranch is Siravo's hideout.
The team heads out to the ranch where they discover that Siravo is comatose under a nurse's care.
Back at headquarters, Tony and Ziva figure that someone created a criminal empire using Siravo's name. McGee discovers that Siravo became comatose after he got into a motorcycle accident. McGee sees that Siravo's money is being drained from his accounts. They figure that the money is being seized by the CIA.
Abby calls Gibbs and tells him that he thinks that she aided in a murder. Abby says that the online game communication was sent through an open forum and that she accidentally ordered someone to kill Flores. Gibbs calls Kort and tells him that he knows that he drained Siravo's money.
Gibbs and Tony head over to Kort at the U.S. Marshall office. Kort approaches one of the U.S. Marshalls and tells him that he wants to take custody of Perry. Perry takes a gun and shoots the Marshalls, he then shoots Kort in the shoulder. Perry tells Kort to give him his money back. Gibbs and Tony arrive, surround Perry and force him to surrender.
Back at the headquarters, the team figures that Perry used his power of attorney to continue to run Siravo's criminal operation. Kort tells Vance and Gibbs that he wanted to capture Perry so he could get back into the CIA.