A young woman's body is found in a drainage ditch clad in only a bracelet, showing signs of having undergone an abortion, and totally drained of blood.

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.