An NCIS agent hurriedly slips a package in the mailbox as an SUV chases him down. The driver pulls out a gun and shoots the agent dead from the car before he could return one of his own, then the shooter comes close to him and shoots one at close range.

The force place black bands in memorial for Special Agent Patterson. Ziva asks Tony if she knew Agent Patterson to which Tony replied only few times in instructions and awards, but he seemed a nice guy. Tony sees that he has a message from a law firm in London. The team investigates the scene where Patterson was killed. Gibbs asks the team why they were late and Tony takes responsibility for being stuck in traffic although it was originally McGee who arrived late at NCIS. Ziva says that a witness reported a black SUV leaving the scene but he claimed he did not hear any shots fired. Gibbs suggests that a small gun would not make a noise and it would not need a silencer, as Ziva was thinking. The team figures that Patterson was killed by a professional killer. Ducky finds a business card of a Homeland Security Agent named Lemming in Patterson's hand. Gibbs gives it to Tony to call the number. DiNozzo misses the cell number on the back of the card initially and gets a Gibbs stare.

An officer comes up and tells Gibbs that some weird Goth lady is trying to cross the security barricade claiming she was also NCIS - but he certainly does not believe that could be possible. Gibbs takes a look and its Abby. She tells Gibbs that Patterson was going to see her before he died. Abby said she had a professional relationship with Patterson but never met him. Abby says that Patterson wanted to show her something and wanted to meet her last night but she told him to meet in the morning.

Tony calls the London law firm but it's past office time so they ask him to call back next day. Tony tells McGee that his very rich great uncle died and he thinks he is in the will because he spent some "quality" time with him one summer many years ago. Gibbs arrives and tells Tony to go back to work. Ziva brings the man that owned the business card, Lemming, into the office. Lemming tells Gibbs that he worked cases with Patterson and that Patterson wanted to show him something. Gibbs tells Lemming that Patterson was shot. Abby goes to the morgue and apologizes to Patterson's dead body. She tells Patterson that she thought that he wanted to go on a date when he called. Ducky arrives and tells Abby that they have work to do. Gibbs and McGee go to the ship that Patterson was assigned to. McGee finds photos that Patterson looked at before he died; Patterson had photographed a room on the ship. Gibbs, Tony and McGee go to the room and see that it is full of boxes. Gibbs tells them to go through the boxes. Meanwhile, Abby is given the package that Patterson sent her. Ziva and Abby learn that Patterson dropped off the package near where he was murdered. Abby opens the package and sees that it contains a water color picture of a Western scene. Gibbs looks at the picture and sees a girl reading a book. Abby tells Gibbs that the bullet found in Patterson matches a bullet used in an unsolved murder of a man in Scottsdale, Arizona. On the ship in the photographed room, McGee finds a package of drugs in an airduct of a room while Tony tells him that Patterson was investigating a sailor named Zell. Later, Tony and McGee pretend to be painting the interior of the ship. McGee criticizes Tony's technique, but Tony says that they are just pretending to paint. Zell arrives and enters the room looking for the package as he is approached by McGee and Tony. Zell hits Tony but is quickly restrained by McGee.

Gibbs discovers that the picture was made by an artist named Dina Risi. Ziva tells Gibbs that the man who died in Scottsdale is named Hamilton Cougar. Abby tells Gibbs that she discovered the package that Patterson used was originally sent to Patterson by Dina Risi. Tony brings Zell to the station. Ziva tells Gibbs that Zell was on a frigate when the man in Scottsdale was killed. Zell tells Tony that he didn't know Patterson. McGee tells Gibbs that Zell was at an ATM a hundred miles away from Patterson when he was murdered. McGee tells Gibbs that Patterson wrote an E-mail saying that Zell's commander Weiland obstructed his investigation. Tony tells Gibbs that Dina was recently found missing. McGee says that there is a location that matches the picture that Dina painted. Later, Ziva says that the man that died in Scottsdale was worth several million dollars. She says that the man was killed in a similar way to Patterson. McGee loads up a satellite image that shows that there is someone in the cabin that Dina painted. Gibbs tells the team that they are going to Arizona.

In Arizona, Tony and Gibbs meet Sheriff Boyd. Boyd says that Dina was a protester and that the only way to Dina's cabin is by horse. While getting ready to leave, Tony tells Boyd that the last time he rode a horse was during a birthday party when he was young. A man arrives at the headquarters and says that he is Lemming. This is not the same guy that Gibbs had talked to. McGee calls Gibbs and tells him that the man that they were working with is an impostor. Gibbs tells Tony that he can't believe he briefed an impostor on their case. Boyd helps Tony saddle up. At the station, the team finds that Dina mixes her paint with the indigenous soil. Abby discovers that the soil Dina used is a radioactive substance used to make nuclear weapons. McGee tells Gibbs that they lifted a print from the fake Lemming and that he doesn't have a record. It starts to get dark and Boyd tells Gibbs and Tony that they should set up camp. At night, Gibbs gets a call from headquarters. Ziva and McGee tell Gibbs that if the fake Lemming is a hitman he is probably heading there to silence Dina. Boyd tells Gibbs that Dina was fighting a company called Sunset Mining. In the morning, the team arrives at the cabin and are shot at by Dina. Dina says that she was supposed to meet Patterson. Gibbs says that Patterson is dead. Dina says she started to get sick after using the soil to paint and that there is a local mine that might contain billions of dollars worth of uranium. Gibbs tells the team that it is not safe at the cabin and that they should head back. McGee calls Gibbs and tells him there is a helicopter heading their way. The fake Lemming flies over and shoots at Gibbs and the group with a semiautomatic rifle, hitting Boyd in the leg. As Tony and Dina take cover, Gibbs gets off his horse and shoots the pilot. The helicopter crashes into the mountain and explodes.

Back in the office, Tony looks at the car that he plans on buying after he receives his inheritance. McGee says that the man's real name is Jerome Sachs. McGee says that Jerome is linked to four other unsolved murders. Tony finally gets a call and is told that his great uncle left all of his money to his cousin. Tony says that he owed his uncle money and that his "sniveling" cousin, who just inherited about $35 million, is only calling to collect the $10 thousand plus compounded interest.