Dirk and Richard receive a suspicious package and wonder what to do with it. The phone ring and Dirk tells Richard to get it. He answers it and tells Dirk that it’s David Edwards and he thinks someone is telling him to kill him. Dirk puts him off again and starts cutting open the package. Inside is a stuffed pig and a Valentine card. Richard wonders who would have sent him a card, and Dirk opens it and finds a message saying that he’s a pig.
Dirk and Richard drive to Edwards’ manor and ring the bell. They get no answer and discover that the door is unlocked. Dirk yells for Mr. Edwards and insists that there is no chance that someone tried to kill him because he’s a paranoid conspiracy theorist. He started following him randomly on the street and finally the wealthy Edwards hired him to investigate why the Pentagon has him under surveillance. Dirk believes that his paranoia has escalated and there’s no chance of him being murdered... until they find Edwards’ corpse. The detective declares that something is wrong and examines the desk and then checks Edwards’ wallet. He removes his business card so the police don’t question him and money to cover his unpaid expenses and the bounced check he wrote him. Dirk explains that once the police have investigated, they can come back to investigate the murder, but for now they should flee the scene. He promptly flees the scene and Richard runs after him.
At the Pentagon, security analysts capture Dirk’s image from satellite surveillance, ID him, and start to issue a termination order. However, a woman stops them and says that Dirk might be useful to them... and they can always kill him later.
Three days later, Dirk watches Edwards’ house and sees the police leave. He wakes up the dozing Richard, who wonders who is going to pay for them to solve the case. Dirk points out that there has been a reward offered for the murder, but Richard figures that Dirk is offended that he was proven wrong. When the car won’t start, they push it into the driveway and go inside. Dirk breaks a patio window and they go inside, only to find a woman standing in the kitchen.
Dirk introduces himself and suggests he explain over a cup of tea. As the woman, Kate, makes tea, Richard offers condolences, assuming that she’s his wife. She fumbles for the tea and Richard hands her the canister. When Dirk says that Edwards thought the Pentagon wanted him dead, Kate asks if it was because of his computer program. Dirk, having no idea, agrees with her and takes his tea. She asks Dirk to investigate her husband’s death and Dirk agrees as long as she pays the same amount plus expenses. Kate reminds Dirk that Edwards was paranoid and that he hid the prototype software. Clearly smitten, Dirk agrees with her and assures her that he can be discrete.
Dirk sits at Edwards’ desk, steals his mints, and shades the note pad, revealing the word “reason.” He then looks at the board where Edwards had his conspiracy theories charted. He looks at a chart involving the invasion of Switzerland and realizes that it is the basis of the computer software that Edwards was writing. Dirk explains to Richard that Edwards developed a piece of software that allowed someone to specify the decision the user wishes to reach, and then it would come up with an irrefutable set of steps to justify the decision. No nation would be safe from tyranny if the wrong people got their hands on the software. Richard doesn’t believe it but Dirk figures that the murderer will return to get the software. He writes down his name on a notepad, shoves everything else off the desk, and tells Richard that when the killer does come back, he’ll see Dirk’s name and come after him.
As Dirk and Richard drive back to the office, they see someone following them. Their pursuers close in and Dirk says that they have to maintain the element of surprise. They arrive at the office and run in past Janice, barricading the door and grabbing whatever weapons come to hand. Janice yells that there’s a woman to see him, and she finally lets herself in. Dirk realizes that she was going to the same place at the same time, a profound coincidence in itself. The woman introduces herself as Emma Reynolds and explains that she believes her husband Oliver is having an affair. Dirk isn’t interested and focuses on the Edwards case, while Richard asks her to explain. Emma tells him that Oliver has been acting irrationally and claiming he doesn’t remember where he’s been. Richard admits that they’re in the middle of a big case, but Emma breaks into tears and says there must be a reason. As soon as she says, “reason,” Dirk says that he’ll take the case because it is somehow connected with Edwards’ death.
Dirk and Richard begin surveillance and Dirk insists that they’re investigating Edwards’ murder. As they order pizza and Dirk haggles over the free delivery, a man secretly takes photos of them. Oliver comes out with a young woman and Dirk tries to follow him in the car and sends Richard to run off after the woman, who is riding a bicycle. Dirk can’t get his car started and Oliver comes over and offers him a lift. They walk over to Oliver’s car and he explains that his horoscope predicted that he would help a stranger. Oliver shows Dirk the magazine article on Terence Brown, the astrologer who has written accurate horoscopes every day. Dirk isn’t impressed and Oliver admits that he didn’t believe it at first. However, a month ago predicted that he would have a new romantic possibility, and he met Maria the pole dancer later that day. When Dirk takes notes, Oliver realizes that he’s a private detective. At that, Dirk offers his services.
Back at the office, Dirk includes Terence in his investigation chart and Richard is shocked that they’re collecting payment from two clients to investigate the same case. However, Dirk explains that they’re two different cases because Oliver hired them to find out why his horoscopes are coming true. A deliveryman arrives with the desk and chair that Richard has ordered for himself and he sits himself down opposite Dirk. Dirk is less than thrilled and warns that the killer has no doubt shaded the notepad and will be by any minute.
That night, Richard watches from the window while Dirk analyzes the handwriting on the Valentine card. He goes to get a pizza and assures Richard that no one will kill them until they have the software, and they’ll never have the software so they’re safe. As Dirk leaves, someone watches from a parked car.
Richard hears someone enter the outside office and goes to investigate. Someone knocks him out from behind.
Dirk returns with pizza and discovers that someone has ransacked the office. He hears someone behind him and clubs him with a lamp, and realizes that it’s Richard. Dirk is happy that the murderer came after them because he planted a hidden surveillance camera. Unfortunately, Richard turned his new chair to block the camera. Dirk takes out a knife and stabs the chair repeatedly, but then finds a bug inside. He smashes it and adds the new clues to his board. Richard figures that the Pentagon attacked them and calls Susan to warn her. Dirk figures that the Pentagon would have heard him says that they don’t have the software, which means the attacker isn’t from the Pentagon.
Emma comes in and asks Dirk if he’s made any progress. Dirk tells her about the horoscopes and gets around to telling Emma that Oliver is having an affair. She breaks into tears and Dirk motions for Richard to give her a huge. Richard refuses and Dirk tries to offer a comforting gesture without any success. Oliver comes in to tell Dirk that his new horoscope says that his dark secret will be revealed. He figures that Emma knows he’s having an affair, and then sees Emma. Richard makes it clear that they’re separate cases, while Oliver insists that his horoscope is responsible for having his affair. She slaps him and leaves, and Oliver shows them his other horoscope, which says his wife will slap him. Dirk doesn’t believe it and assures his client that he will prove the events have nothing to do with astrology.
The next day, Dirk goes to Terence’s office and limps inside. Richard is waiting for him, having taken a circuitous route to avoid surveillance. Terence agrees to see them and explains that they e-mail personalized horoscope to over two million clients. Dirk insists that that horoscopes can’t determine human behavior, and asks if they’re generated by a computer program. Terence confirms that they are and Dirk says that the software is responsible for his client’s distress. A plumber calls Terence to tell him that his pipes burst and he has to go, and Dirk points out that his horoscope should have predict it. Once Terence runs out, Dirk breaks into the server room, unbuckles his pants, and removes the sledgehammer that has been causing him to limp. He explains that he arranged the burst pipe and then smashes the server. Dirk then explains that he’s conducting a scientific experiment to prove that the horoscopes aren’t predicting the events in Oliver’s life.
As the two men drive back to the office, they spot someone following them and flashing their lights. Dirk tries to speed up but the car gives out again and the pursuing car pulls over. It’s DI Gilks, who says that he’s been informed that they’re withholding evidence relating to Edwards’ murder. They found a to-do list that Edwards wrote saying he was sending the software to Dirk. Dirk points out that he hasn’t received any such software and Gilks demands to know who hired him. After Gilks threatens to arrest him, Dirk admits that Kate Edwards hired him... and Gilks tells him that the real Mrs. Edwards died in a car accident a year ago. Dirk switches tracks and says that he has no client and is just trying to collect the reward. Gilks refuses to arrest him, figuring that Dirk’s meddling will get him killed and then he’ll have some new leads. Once they’re alone, Dirk figures that Kate was working for the Pentagon and looking for the software prototype. He calls Kate’s phone number and asks for a meeting to explain a new breakthrough in the case.
Dirk and Richard go back to Edwards’ manor and Kate comes in. When Dirk points out that she looks well for a dead woman, she falls down dead, a bullet wound in her back. They hear someone outside and Dirk runs for the front door. Richard goes after him and they get into the car and drive away as the killer shoots at them. They get out onto the street and Richard wants to go the police, but Dirk has little faith in Gilks. Instead he follows a passing white car until it pulls up to a pub. Dirk insists that it’s exactly where they need to be and approaches the driver as he gets out. The driver notices them and goes in, and Dirk calls Oliver and invites him to come to the pub.
Inside, Dirk explains that if Oliver comes in wearing some extravagant headgear and talking about a rhinoceros, then he’ll have proven that connections are not predetermined. Oliver comes in wearing a fez and holding a stuffed rhinoceros, and explains that his horoscope predict exactly that. Dirk tells him that he destroyed the server and it couldn’t have sent out any horoscopes. He sent the e-mail to Oliver, and it became a self-fulfilling prophecy. A sheepish Oliver removes the fez and wonders what is happening to him. Dirk is satisfied that life is being restored to its natural chaotic state and gives Oliver the bill. Now they’re left to wonder how it all relates to Edwards’ murder, and the partners watch as the driver looks at them again and leaves the bar.
The next day, Richard arrives at the office and Dirk tells him that he’s received another Valentine card calling Dirk a pig and written in hand. He assures Richard that since they don’t have the software, they’re perfectly safe. He prepares to check the hidden camera and find out who delivered the card. However, as he takes one of Edwards’ mints, he finds a memory stick hidden inside. The name of the software, “total reason,” is written on the label. Richard wants to take it to the police, but Dirk assures him that things have gone nicely out of control.
Oliver arrives and tells them that he has to die. He shows Dirk all of the new horoscopes predicting his death, but Dirk reminds him that he already proved they weren’t coming true. When he asks Oliver about the rhinoceros, Oliver has no memory of the stuffed rhinoceros or of meeting them in the pub the previous day. Dirk tells him to embrace the chaos and realizes that Edwards didn’t want to die. However, Edwards believed the Pentagon wanted to kill him, and now Oliver believes he’s going to die. He crosses the Pentagon off of his board and realizes that Edwards was killed for something other than the software. He looks at the bounced check and realizes that Edwards had gone broke because someone was stealing from him.
Dirk and Richard take Oliver outside to the car. Oliver smells the Brie that Dirk carries, much to the detective’s surprise. They spot the driver from the previous day parked outside of their office. Dirk throws a brick at his car window to provoke a reaction and the man gets out of the car and draws a gun. Dirk, Richard, and Oliver run into an abandoned building but the man, Matthew, comes in after them and demands that they hand it over. Dirk explains that Matthew is Edwards’ accountant and believed that Edwards hired them to find out who was stealing from him. Matthew suspected that Edwards was onto him and killed the woman, Kate, because he figured she was working for them. He doesn’t believe their denials and asks for the evidence that he killed Edwards. A hysterical Oliver complains that he can smell cinnamon and Matthew admits that he was eating a cinnamon roll at the coffee shop. Dirk asks Oliver how long he’s had an acute sense of smell, and then hands his camera to Matthew. When the accountant is distracted, Richard manages to disarm him. Oliver runs out of the building and back to the office while Matthew escapes with the camera.
Dirk and Richard follow Oliver to the office and finds him ready to jump out the window. Richard tries to stop him, saying he doesn’t want to die, but Dirk explains that Oliver’s memory loss and acute sense of smell mean that he has a brain tumor. Oliver tries to take it all in, slips, and falls onto Matthew standing in the street below. Matthew drops the camera, which shatters.
As they wait outside the hospital, Dirk eyes the broken camera and admits that they’ll never find out who sent the Valentine card. Emma runs up and Dirk assures her that Oliver survived the fall and has a brain tumor. However, the brain tumor caused all of his recent behavior. After some brain surgery, the doctors have confirmed that Oliver will be okay. That leaves the matter of the bill. Emma points out that Dirk is charging her and her husband to investigate the same case, rips up the bill, and goes to her husband. That leaves the reward for finding Edwards’ killer. Richard points out that Matthew wouldn’t have killed Edwards if Edwards hadn’t hired Dirk. Dirk says that thanks to his investigation, Oliver was diagnosed and his life was saved. That leaves the software prototype... until Dirk discovers that he’s lost the memory stick. He remembers bumping into a man coming out of the hospital and runs back to see him getting into a black SUV and driving off.
Dirk and Richard go back to the office as a disgusted Janice leaves for a long lunch break. Richard notices her notepad, shades it, and discovers that she has been writing “pig” repeatedly. The notebook is filled with notes alternating between Janice declaring her love and her hate for Dirk. He also finds a drawer filled with stuffed pigs. Janice comes back in to get her bag and they both pretend he didn’t find anything.
Dirk calls Richard in to listen to the radio, which has a news broadcast about the American conquest of Mexico. According to the news, even the U.S.’s staunchest critics have to admit that they have legitimate reasons for invading Mexico.