Det. Murdoch investigates the murder of Richard Dawkins who was beaten to death at the dinner table by two masked men just as he was about to make an important announcement to his business associates. Since nothing was stolen Murdoch's new boss, Inspector Hamish Slorach, calls the killing an assassination. Dawkins was rumored to be selling his chandlery business. The harbor master says Dawkins was anything but a saint and the police should look to the seedier side for a solution to his death. Const. Jackson is badly beaten by two thugs which seems to confirm Murdoch's suspicion that the men who beat Inspector Brackenreid are the same ones who killed Dawkins. When they find a dead woman on the shore, Dr. Grace determines she was clubbed to death the night before the attack on Dawkins and was manacled before she died. Meanwhile, suffragettes recruit Julia to their movement and she is joined by Emily Grace. Receiving little support politically, they decide to hold a protest march. They are all soon in jail.

The police continue their search for Mick and Tim O'Shea but Inspector Brackenreid is also out on his own looking for them. Murdoch finds someone who confirms that the O'Sheas killed Richard Dawkins but the man also suggests that the O'Sheas aren't working alone. Mrs. Cecily McKinnon, the harbor master, says she knows nothing of extortion on the docks but when pressed, points the finger at one of the merchants, Lionel Jeffries. When the O'Sheas are found dead, shot through the head, Brackenreid becomes the number one suspect. Meanwhile, the ladies who participated in the suffragette protest - including Drs. Ogden and Grace - are still in jail. In court, they find that Leslie Garland is one of the Crown attorneys prosecuting them. They get a bit of a boost when Clara Brett Martin, the first woman lawyer so recognized in the British Empire, offers to represent them.

Legendary U.S. lawman Bat Masterson is in Toronto and claims to have seen the equally legendary Butch Cassidy and the Sundance Kid. Masterson is now a newspaperman and he's already filed a story about the sighting with his New York paper. Murdoch is doubtful about the whole thing and is under the impression that Butch and Sundance had fled to Argentina the previous year. Brackenreid is keen however - and just a bit starstruck - and they set off to find the two men Masterson says he saw. After the Bank of Toronto is robbed - and that quickly followed by a train robbery - Masterson's claims appear confirmed. Masterson himself thinks otherwise and comes clean. Meanwhile, Julia and William's wedding day is fast approaching but they have yet to select just where they will be married. Julia has an idea however. The men of Station 4 plan Murdoch's bachelor party.

After testifying at Mary Thompson's trial for murdering her husband Percival that the woman is criminally insane and should be committed to an asylum, Julia Ogden receives an anonymous postcard saying she has condemned an innocent woman. Julia and Detective Murdoch re-examine the case and find an anomaly in the time-line but the Crown Attorney isn't interested as he's convinced the woman is guilty. Further investigation reveals that Percival Thompson's business partner, Alexander Wainwright, automatically assumed 100% of their business upon Thompson's death - an agreement they signed just one week before the murder. Wainwright promptly vanishes. With the assistance of the indefatigable Mrs. Brackenreid, who has clearly taken charge, Julia is in the final preparations for her wedding. She and William make it to the altar on the big day but midway through the ceremony they realize they overlooked something very important in the Thompson case.

During their honeymoon in New York, Murdoch and Ogden uncover a deadly conspiracy threatening U.S. President Teddy Roosevelt, while Brackenreid and Dr. Grace investigate a murder by motorcar back in Toronto.

Detective Murdoch investigates the death of a man found dead on a park bench. Dr. Grace initially determines that he was stabbed in the abdomen but subsequently concludes he was actually suffocated. He also has dried blood on his index finger and three pages from a Mark Twain novel on him. When he returns to the station Murdoch meets Owen Hume who reports that his employer, lawyer Randolph Sampson, has been missing for two days and subsequently identifies him as the man in the park. Meanwhile, Constable Crabtree investigates the disappearance of a corpse, that of Prof. Andrew Richardson, from the medical school. His brain was the object of a medical study by Dr.Dempsy who is researching the brains of highly intelligent people. When it turns out that Sampson and Richardson are the same person Murdoch learns that he's dealing with a group of admirers who wanted to see him in action so to speak. Julia continues her suffrage activities and lawyer Clara Brett Martin confirms that it's possible for a woman to run for elected office.

During the renovation of the police station, the body of a long-missing constable is discovered in the foundation which leads Murdoch to investigate that station's veterans' past and the gay community of that time.

Detective Murdoch investigates the apparent murder of an inventor who is found sitting in a chair he invented. That chair was meant to provide a mild electrical current as a rejuvenation technique but Dr. Grace is certain that he was in fact electrocuted. He had a young woman with him the night he died but the investigation leads him to inventor Thomas Edison and the main suspect - his son Thomas Edison Jr. Meanwhile, the mayor tells Inspector Brackenreid to speak to Murdoch about Julia's plans to run in the upcoming election - fully expecting he will exercise his authority as her husband. Murdoch makes it clear to everyone that he has no intention of interfering and will support Julia in her campaign.

Inspector Murdoch investigates shooting of vaudeville comedian Bert Grady who is found dead on the street, shot three times in the chest. Grady had just finished his performance at the Bradley theatre, with Constables Crabtree and Higgins in the audience. The shooting looks like - or was made to look like - a robbery. He was not well-liked by others in the show, including a young juggler by the name of W.C. Fields and Ed Ward, Grady's one time comedic partner who is now far less popular on his own. The police find Grady's hotel room ransacked and suspect someone may have been out to steal his jokes. Would-be comedians Crabtree and Higgins join the show undercover and quickly identify Grady's mistress, Eleanor Moffat, wife of the show's manager, Lewis Moffat who became aware of their affair a week ago. A buried body gives them the clue to solving the crime.

While investigating a mysterious death in Markham, Det. Murdoch discovers a hidden ornate and booby-trapped laden building that could contain the Holy Grail.

The suspicious death of a land surveyor just outside Murdoch's station house sends him and Crabtree to rural Northern Ontario to investigate both the crime and his mysterious dying words.

During a women's fashion show for undergarments, a model is found dead.

Detective Murdoch investigates the death of Nurse Collins who seems to have been killed by a patient, Rose Maxwell, at the insane asylum where Dr. Ogden works. Somehow, the extremely violent Rose managed to get out of her room and knock out the guard, Samuel Drainie. It appears she then used his knife to stab nurse Collins 11 times; there were also bite marks on the body. Rose, who killed her entire family, also blames Dr. Ogden and Dr. Grace for her current predicament and has vowed revenge. Crabtree finds all of the women's fingermarks on the murder weapon but it's the frequent visits from Rose's brother Cedric that initially draws his attention. The solution to the mystery lies elsewhere however.

Brackenreid's abrasive nephew joins Station 4's crew just as Murdoch investigates a gang of female jewel thieves who seemed to have just murdered their ringleader.

Det. Murdoch revisits his past when a murder investigation at a church reunites him with the Jesuit priest who mentored him as a young altar boy.

George Crabtree investigates a suspicious death in the world of entertainment wrestling.

Julia and her colleagues are going to vote for a female candidate as a gesture for women's suffrage; meanwhile, Murdoch investigates the death of a man who may be one of Terrence Meyer's minions.

During a hunt for a killer who collects macabre trophies, Murdoch becomes a target. Meanwhile, Crabtree discovers the recently returned formerly presumed dead husband of his love is an abusive brute.