The episode begins with a man waiting in his car and there is a license plate number written on his matchbox. Just ten Fornell arrives on the opposite street and collects his food and begins to eat. This strange man gets down, walks towards Fornell’s car and shoots him. The windshield is shattered. Just as the man begins to think that Fornell is dead, Fornell shoots back and the man is dead. Next, NCIS arrives at the scene. The shooter was Navy seaman Tyler Brown. Fornell thanks Gibbs for coming. Duckie checks Tyler’s eye and he finds them dilated; looks like Tyler was using some stimulant.
Fornell tells them that he doesn’t recognize the shooter. They then find the matchbox with the license plate number and Fornell tells them that it is his number. This means that Fornell was being targeted. They learn that Tyler worked at a nearby bar. Gibbs and Fornell go to the bar and talk to the bartender. He tells them that Tyler was a bouncer. One of the customers, who is sloshed, tells them that Tyler loved to beat the crap out of people and that he used to trade in speed alongside. Just then Diane walks out of the bathroom; she is their mutual ex-wife. This cannot be coincidence that all three are at the same place at the same time. She tells them that she works for the IRS and that she is here for an audit.
The bartender arrives and addresses her as Mrs. Fornell and tells her that the owner is not interested in selling the bar. Well, we thought it was an audit? Gibbs states that this is also obstruction of justice. They take her for interrogation. McGee arrives and tells the team that Diane is using two aliases; Diane Fornell and Diane Gibbs. Tyler was reprimanded several times for fighting and arriving late for duty. He was in the process of dishonorable discharge. So, it is interrogation time and this task is assigned to Tony!! She is pissed at the way she is being treated. She tells Tony that her husband and daughter are at a wedding and she stayed back as she wanted some time for herself. Just then Vance enters and tells them that the interrogation is over.
Diane calls her boss from Vance’s office and she gets clearance to talk. She tells them that she is not an IRS auditor but she is an agent. Gibbs and Fornell are shocked. She tells them that she was working undercover in the bar and that there has been a lot of identity thefts in the bar. She used Fornell’s name as making a new id is expensive. Fornell is enraged about the fact that her investigation almost got him killed. This means that she is on the right track. Vance declares that the three of them will work the case together. Diane exains to the team whatever has been happening and it seems that Tyler has been taking information from the driver’s licenses of the people coming to the bar. Gibbs and Fornell go to check the fake tax return checks and Ziva and Dianne go to check the cashing outlets.
At the outlet, Diane tells Ziva that she is taking a break from her present husband Victor. She then feels that she might have made a mistake by getting married again and that now she is not able to go out and act crazy. They then talk to the clerk and shows him that fraudulent check. He remembers that these belong to a man named Oliver Lambert. He also shoes them the surveillance footage. At NCIS, they realize that Oliver is the theft ringleader and that he is also interested in horses. McGee declares that Oliver’s bank accounts have been emptied. Gibbs and Fornell feel that Diae is in danger and that she should not be left alone. Both the ex-s are reluctant to keep Diane with them and so this task goes to McGee.
She is complaining that her husband doesn’t compliment her anymore and she feels that there is something wrong with her. She feels that she is not attractive anymore. McGee tries to assure her that she is attractive; at least on the outside!! She wants a hug and McGee is reluctant. She insists and she tells him that his parents failed. On hearing this, he hugs her. Next day, Gibbs and Fornell find them on the couch sleeping together. Fornell is aghast and he snaps. McGee tells him that it is not what it looks like. Diane and Formnell get into an argument. Gibbs tells them to cut it off and that Abby has a lead on the accountant. They then meet Tony, who is standing in front of a house. he tells them that there is an overdue payment on the rental house. Tony breaks open the door and see that it is freezing inside.
They find out that Oliver had rented this apartment for his frozen fish collection. But then McGee opens another chest and finds the body of the drunk man at the bar in it. In the morgue, McGee insists that nothing happened between him and Diane. He then tells them that the dead man was Viggo Kiln and he was working with Oliver. He was the one who used to chat up with people at the bar and obtain information and then file the fake tax returns with that information. There were two bullets found in his head and the gun belongs to a man named Oliver Lambert; the missing accountant. Looks like Oliver was trying to tie up loose ends. But the frozen fish in the apartment still seem to be “fishy”.
Diane comes up with a theory about the frozen fishes. She finds out that these fishes are being exported to fishing villages on the borders of countries like North Korea, China, Syria and Iran. She leaves to talk to a customs agent she knows and she “orders” Fornell and Gibbs to check the shipments. In the lab, Abby has found cell phones in the fishes. All the fishes had a phone hidden inside but they were all from the same manufacturing batch. Someone used one of these phones to call Oliver and Abby manages to track the location of the caller. They stake out a park. Fornell talks about the rumours that Victor is leaving Diane. He also thinks that Diane deliberately asked for a transfer into Gibb’s jurisdiction, hoping to run into him. just then Oliver Lambert arrives and all of them go towards him.
He seems to be high and he doesn’t remove his hands from his pockets and all of them draw their guns on him. he tells them that he gave them this week’s payment but they are still worried. He thinks they will try to kill him. Gibbs orders him to remove his hands from the pockets. He moves his jacket, to expose a bleeding stomach and he drops on the park bench. At NCIS, Duckie confirms that Oliver was killed due to multiple stab wounds. There was a pen drive found in his wallet and it shows that he was embezzling money for someone but his boss’ name has been left out. We also learn that Oliver was about to turn himself in. they also find out about another shipment and this time it is DVDs and luxury bath items. Abby finds out that all the fishes were from a fish distributor named Avis Boyle.
They think that he was Oliver’s client and he is a smuggler. But they don’t have much to arrest him. Diane has a plan. She knows that Boyle is going to require another accountant and that she is going to approach Boyle for the same. Gibbs says that he too will go with her to meet Boyle. Next, Diane and Gibbs are at a wedding. Boyle arrives and Diane approaches him. Boyle goes to get his boss. They then see the boss arrive; it is the guy from the check cashing place, Gordon Freemont. He recognizes Diane as the IRS special agent who visited him earlier. He draws hi gun and hustles her across the floor. But just then Gibbs proposes to her in front of everyone; just like he had proposed to her the first time.
She says a yes and she runs towards Gibbs. Gordon is in an awkward position and is forced to let Diane go. Gordon is about to leave, and the rest of the team arrive and arrest him. At NCIS, the trio tells Vance that Boyle wasn’t the boss; he was one of the four distributors from the smuggling ring. Gordon was the one running the show. At the basement, Diane meets Gibbs and tells him that she is touched that he remembered how he proposed her. He tells her not to drive people away from her as he did. She tells him that he is not that bad. Diane then asks him if he is going to spend the rest of his days alone. He tells her that he is not alone. The episode ends.