Murdoch struggles to work with the new coroner and clashes openly when a cement block found near the water contains the remains of not one but three men.

Julia, Emily and four of their friends head off to a remote cabin on an island. It's a party to celebrate Lavinda's upcoming wedding to Cedric Maxwell. Cedric's sister is part of the party and she and her brother own the family retreat. Julia is obviously not happy and confides in Emily. Before long however, the women are being killed, one by one. Still reeling from Julia's rejection of his marriage proposal, Murdoch immerses himself in his work. When a drunken Crabtree challenges Leslie Garland to a curling match, he has to put a foursome together. Murdoch declines an invitation to join but applies his scientific approach to helping them play better.

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.