Three years after losing his job with the San Francisco Police Department because of his obsessive/compulsive disorder, Monk is working as a private consultant investigating the murder of a young woman named Nicole Vasquez. Shortly after determining that the murderer was at least 6'3", smoked menthol cigarettes, and wore slippers, Monk receives a call from his former boss, Captain Stottlemeyer, who reluctantly requests his aid in discovering the would-be assassin of mayoral candidate Warren St. Claire. While at least three people (including Mrs. St. Claire) seem to have sufficient motive to kill the candidate, the Vasquez murder seems to be unmotivated. Despite the captain's skepticism, Monk is certain that the cases are related. The police get a lead on the would-be assassin, but he manages to escape, in part because of Monk's fear of heights. Sharona convinces the deputy mayor to let Monk continue his investigation despite Captain Stottlemeyer's objections. After Monk has gathered the suspects together to recreate the crime scene, the hitman takes a shot at his accomplice and Sharona, playing Lois Lane, follows him into a sewer. Overcoming his revulsion, Monk goes in after them, placing Kleenex on the rungs of the ladder to protect his hands and feet on the way down. But Kleenex won't protect his shoes or the cuffs of his pants from the filthy, six-inch deep water. This novel act of courage moves Monk one step closer to recovering his emotional stability – and getting his old job back.

Three years after losing his job with the San Francisco Police Department because of his obsessive/compulsive disorder, Monk is working as a private consultant investigating the murder of a young woman named Nicole Vasquez. Shortly after determining that the murderer was at least 6'3", smoked menthol cigarettes, and wore slippers, Monk receives a call from his former boss, Captain Stottlemeyer, who reluctantly requests his aid in discovering the would-be assassin of mayoral candidate Warren St. Claire. While at least three people (including Mrs. St. Claire) seem to have sufficient motive to kill the candidate, the Vasquez murder seems to be unmotivated. Despite the captain's skepticism, Monk is certain that the cases are related. The police get a lead on the would-be assassin, but he manages to escape, in part because of Monk's fear of heights. Sharona convinces the deputy mayor to let Monk continue his investigation despite Captain Stottlemeyer's objections. After Monk has gathered the suspects together to recreate the crime scene, the hitman takes a shot at his accomplice and Sharona, playing Lois Lane, follows him into a sewer. Overcoming his revulsion, Monk goes in after them, placing Kleenex on the rungs of the ladder to protect his hands and feet on the way down. But Kleenex won't protect his shoes or the cuffs of his pants from the filthy, six-inch deep water. This novel act of courage moves Monk one step closer to recovering his emotional stability – and getting his old job back.

A panicky woman driver goes off the road thanks to a skid block placed by her husband, former police commissioner Harry Ashcombe. The next morning Dolly Flint, a psychic on first name terms with Captain Stottlemeyer (who has arrested her three times on bunko charges) wakes up in her car next to the site of the staged accident. Dolly insists that she was led to the site by the dead woman's "aura", but Monk is suspicious. At the memorial service held in the dead woman's expensive home, Monk figures out what the audience already knows – that Ashcombe is the murderer. With the aid of Ashcombe's mistress, Monk, the captain, and Dolly stage a psychic "reading" to catch the killer. Eight out of ten.

A 911 call from a judge identifies the man who is about to murder her as rich and obscenely fat financier Dale Biederbeck. But "Dale the Whale" weighs over 800 pounds and can't get up from his bed, making it impossible for him to have commited the murder, despite the 911 call and the testimony of a ten-year-old witness who saw an extremely fat man through the window of the judge's house. The fact that Biederbeck sued Monk's wife for libel after she criticized his ethics in a newspaper article gives Monk added incentive to find him guilty. While Monk and Captain Stottlemeyer try to figure out how Dale could have committed the murder, Sharona gets her chance to play Lois Lane, or rather Florence Nightingale, by briefly serving as Biederbeck's nurse instead of Monk's. She also finds herself attracted to Dale's private physician, Christian (kristy AN) Vezza.

Officer Adam Kirk, an old friend of Stottlemeyer's, steps off a ferris wheel to find the young man he was riding with dead from a knife in his chest. Stottlemeyer has no choice but to arrest his friend and advise him to remain silent. He enlists Monk to investigate the case unofficially, even though Monk believes the hair-triggered cop is guilty. Matters are complicated when a criminal Kirk is charged with beating is released for lack of evidence, and more so when Monk discovers that the bruises on the victim's body were self-inflicted. Meanwhile, Stottlemeyer is forced by his conscience to state that Monk is not ready to rejoin the force and to endure the resentment of both Monk and Sharona as a result of this decision. When Monk, still furious with Stottlemeyer, figures out what really happened, he and Sharona return to the carnival and Sharona climbs aboard the ferris wheel to spot the escaping criminal because Monk is too afraid of heights to do it himself. But the criminal is hiding...

After attempting to prepare his dead wife's favorite dinner in her old house to celebrate the anniversary of the day they met, Monk is arrested for unlawful entry and is taken to Medford Psychiatric Institute for forty-eight hours of psychiatric observation. His roommate, overly empathic John Wurster ("I'm a detective, too!"), informs him of an unsolved murder four years earlier, while another inmate, Manny, involves him in a quest to discover Santa Claus on the asylum roof. In addition to Dr. Lancaster's orders not to play detective during his stay at Medford, Monk finds his quest to solve the two "cases" thwarted by apparent slips of memory – a picture he doesn't remember drawing and another patient's necklace that has found its way into his pocket. After the necklace incident, Monk finds himself strait-jacketed in the "choir room" as the doctor's sinister aide goes upstairs for four cc's of Thorazine. Meanwhile, Sharona, who hears about the murder on a visit to Monk, examines the mur...

When billionaire software magnate Sidney Teal is shot dead by ex-cop Archie Modine after allegedly turning mugger and another policeman mysteriously flees the scene, Stottlemeyer calls in Monk to investigate. Not only is the idea of a billionaire turning mugger hard to swallow, the circumstances of the mugging are suspicious. Why, for example, would a mugger wear knee and elbow pads? Meanwhile, Sharona threatens to quit (this time for sure) when her paycheck bounces, and Stottlemeyer is hounded by reporters demanding information on "Fraidy Cop". Unable to continue the investigation without Sharona's help, Monk returns to the seemingly unsolvable mystery of his wife's murder only to find that his "new" clue isn't new; he's already talked to writer Kelly Street three times. Sharona finds that selling lamps isn't nearly as much fun as working for Monk (with or without money) and comes to the rescue with a new clue involving Teal and Modine.

When a lawyer and his assistant are murdered, suspicion falls on a disgruntled client whose burnt file is found in the wastebasket. When the suspect, Grayson, is also murdered, Stottlemeyer is certain that Grayson's neighbor, a pretty blonde named Monica Waters who has been feuding with Grayson for two years about her garage, is guilty of all three murders. But Monk is attracted to Monica, who bears a slight resemblance to Trudy. Because Monica's absent husband had OCD, she understands Monk in a way that Sharona can't, which of course adds to the attraction. Even her garage is perfect, exactly the way Monk would want his garage to be organized if he ever had one. A touching bond forms between them until a call from Stottlemeyer leads him to suspect that Monica may really be the murderer.

A woman is murdered during the San Francisco marathon and Monk suspects her married lover, Trevor McDowell, even though he was running in the race. Although McDowell disappears from the video tape of the race less than halfway through and reappears only at the end, the data from a computer chip indicates that he was present at all checkpoints during the race. After interrogating the murdered woman's ex-husband as a possible suspect only to find that his alibi is probably credible, a frustrated Stottlemeyer provides Monk with a brilliant suggestion – that the computer chip was passed off to someone else during the race. Monk meanwhile has the chance to visit his hero, an aging runner from Nigeria whom Sharona briefly suspects may be the murderer's accomplice – a theory Monk refuses even to consider. When Monk figures out what really happened, he must catch the murderer himself to prove his theory.

Monk's beach resort vacation with Sharona and Benjy turns into work when Benjy witnesses a murder. But with no body to be found and "the cleanest crime scene in the history of crime", Benjy can't convince anyone except Monk and the hotel's kooky security chief that he's telling the truth. Believing that Benjy's imagination is working overtime and determined to enjoy her vacation, Sharona takes unneeded tennis lessons from yet another Mr. Wrong while Monk and his new assistant follow what turns out to be a false lead. Benjy spots the body only to have it disappear again, and the security chief reveals Monk's own room to be contaminated with some of the "fourteen bodily fluids" detected by her sonar machine. When Monk figures out who stole four bags of lime from the grounds supervisor's shed, he solves the case. Unfortunately, his time at the hotel is almost up and the body still has not been found.

A wealthy businessman is apparently killed in an earthquake, but Monk is sure that he was murdered by his wife. The trauma of the earthquake temporarily worsens Monk's condition by causing him to talk gibberish, but he recovers soon enough to communicate his suspicions to the beleaguered captain, who has his hands full with fires, false alarms, and looters. Meanwhile Sharona is forbidden to enter her apartment because of earthquake damage, so she and Benjy are forced to spend the next few days with Sharona's snippy and competitive sister, Gail. They are quickly joined by Monk and Sharona's latest Mr. Wrong, whom the viewer knows is really the lover of the dead man's wife. Complications arise when the conspirators decide that Sharona knows too much and Monk, who has mentally reconstructed the crime, again loses the power to speak English after going through an aftershock. The captain, who has just begun to investigate a second murder in Sharona's neighborhood, receives an untelligible c...

Country singer Willie Nelson, who portrays himself, becomes the prime suspect when his manager is murdered, but the only witness is a blind woman who claims to have overheard a scuffle and can identify Willie as the murderer by his voice. At first Stottlemeyer (who is on the case despite a broken arm) is reluctant to arrest the famous singer on such shaky evidence, but a video tape convinces him that Willie must indeed be guilty. But for Monk, the fact that a note used to lure the victim to his death refers to him as "J. Cross" while Willie refers to him as "Sonny" casts doubt on the blind woman's story. Determined for the sake of his dead wife, Trudy, a devoted fan, to prove the singer innocent, Monk interviews the blind woman and investigates the manager's less than reputable background, searching for the clue he needs to clear the singer's name.

Thinking that he's just accompanying Sharona to the airport to pick up her aunt, Monk discovers to his dismay that she's the one making the flight. The choice between being on his own without Sharona or flying cross-country to New Jersey is a tough one, but he overcomes his fears and boards the plane. After annoying the passengers and crew with his first-time-flyer questions, he becomes even more unsettled after small anomalies convince him that the Frenchman sitting across the aisle has murdered his wife and the woman accompanying him is an imposter. He calls Captain Stottlemeyer only to find that it's the captain's day off but manages to persuade Lt. Disher to search the airport for a body. With on-and-off help from Sharona (who would rather be "helping" Tim Daly decide whether to accept a role in an upcoming film) and from the extension cord salesman in the seat next to him, Monk tries to provide the evidence Disher needs to order the arrest. Meanwhile another murder is committed wh...