When an English teacher was believed to have committed suicide at Trudy's former high school, the assistant principal called Monk in to investigate. He quickly concludes that it wasn't a suicide based on the suicide note left by the victim. He began to suspect the science teacher, Derek Philby to be the real murderer.

A friend of the mayor asked him to investigate the death of his son in Mexico. He then, sent Monk in to investigate. With all his suitcases stolen, Monk found himself having difficulties concentrating on the case. In the meantime, someone is also trying to kill him.

A CEO, Lawrence Hammond and his pretty young wife are murdered at night in a deserted parking lot. While, Stottlemeyer suspects it to be the doing of the CEO's many enemies, Monk believes that the wife was the real the primary target.

Monk is investigating the death of a sarcastic and unpopular ringmaster who was murdered by an acrobat wearing a face mask and a Ninja-like costume. Monk suspects the ringmaster's ex-wife, a trapeze artist billed as the Queen of the Sky who is also a sharpshooter but she has a broken foot.

Karen, Captain Stottlemeyer's wife thinks that her documentary subject, the world's oldest man has been murdered. The captain calls Monk in to investigate. After being thrown out of the house by his wife, the captain has no choice but to stay in Monk's place.

Sharona's sister, Gail who is an actress, is suspected of murdering Hal Duncan, another fellow actor. Apparently, he died after Gail stabs him onstage with what she insists is a retractable knife. Monk begins to suspect that Jenna Ryan, Gail's understudy is the real culprit behind the murder.

Monk suspects that the person behind the mail bombing which killed the rich and beautiful Amanda Babbage is the victim's brother, Brian. However he has been in a coma for four months after getting involved in a car chase with the police.

A secretary hired Monk to investigate the murder of her boss, Elliott D'Souza. She suspected that the playboy/publisher Dexter Larsen is real murderer. Monk suddenly tries to withdraw from the case when Larsen threatens him with nude photographs of Sharona.

Captain Stottlemeyer calls in Monk to help him investigate a series of brutal murders. At first, they all suspected Henry Smalls, an insurance agent whose calendars appear in three of the victims’ photographs to be the muderer, but then he too became a victim.

Nestor Alverez, Monk's paperboy was murdered on his front doorstep by a newspaper thief. Now, Monk has to put up with all the police in his house as everyone assumes that the murderer is really after him.

Molly Evans. Bitty Schram made a special appearance as Sharona Fleming, Monk's former nurse (Schram was a former cast member, who left during the third season). Other guest stars for the eighth season included Brooke Adams, Adewale Akinnuoye-Agbaje, Sarah Aldrich, Dylan Baker, Eric Balfour, Ed Begley, Jr.,

Monk suspects Brad Terry, the star in the TV series Crime Lab S.F. of murdering his ex-wife so he won’t have to share his huge new paychecks with her. However, the actor has a solid alibi. He was with photographers when the victim’s screams were heard.

A middle-aged law student Julie Parlo offers to help Monk becomes reinstated as a policeman with the SFPD if he'll help her find her missing grandmother. Stottlemeyer and Disher suspect the former leader of an anti-Vietnam War group from the 1970s to be the kidnapper.

Captain Stottlemeyer's wife, Karen, is badly injured when her car is struck by a tow truck whose driver has been killed by a sniper. The captain suspects the sleazy union official and his thug to behind the crime, but with Monk around, the real culprit is about to be capture.

Lt. Disher asked for Monk and Sharona's help when his 58-year-old mother married a 37-year-old antique dealer whom he believes to be a con man. Meanwhile, Dalton Padron with his new bride is a marriage counseling clinic for their honeymoon. Sharona and Monk has to pose as husband and wife and join him at the clinic.

A death-row inmate who was waiting to be executed in 45 minutes was murdered. Dale the Whale Biederbeck became the main suspect in the inmate's murder. Dale asked Monk to solve the case and he will provide information about Trudy's murder.