Murdoch ha sido encarcelado injustamente por el asesinato de una bailarina de burlesque, Julia ha sido secuestrada, Brackenreid ha desaparecido, los agentes Jackson y Crabtree han sido aparentemente asesinados y la comisaría número cuatro ha caído bajo el yugo de un concejal corrupto. Los pocos aliados que le quedan a Murdoch se ven obligados a pasar a la clandestinidad mientras trabajan para arreglar las cosas.

Un experto en vinos es envenenado en la boda de su hijo tras amenazar con revelar un fraude en la floreciente industria vinícola canadiense. El detective Watts aprovecha la oportunidad para introducir al abstemio Murdoch en el mundo de la cata de vinos. Mientras tanto, la señorita James se enfrenta a la discriminación racial cuando solicita un empleo.

Un dispositivo de grabación hecho por Alexander Graham Bell ayuda en la investigación de un asesinato en una cena en honor a Helen Keller.

Murdoch investiga a un cirujano cuyos trasplantes de órganos de última generación causan estragos médicos y entran en conflicto con Mary Baker Eddy y el movimiento de la Ciencia Cristiana.

A spate of murders staged as suicides leads Murdoch to suspect a sequential killer targeting the elderly.

In an attempt to solve a murder, Crabtree and Constable Brackenreid go undercover at a boys school.

Murdoch investigates a car accident and uncovers sinister motives.

Brackenreid begins painting again and gets the attention of a wealthy patron while investigating an artist's murder.

After obituaries are published in advance of two men's deaths, Murdoch discovers more intended victims with a member of Station House Number Four among them. He must keep them alive before their predicted demise.

Murdoch investigates a death which may have been caused by a high-speed travel device.

Murdoch and Brackenreid find some unsportsmanlike behaviour while investigating the violent death of a cricket player on the pitch.

Murdoch investigates when a statue of the Virgin Mary gifted to his church begins miraculously weeping.

When the judge of a cooking contest is poisoned, Murdoch realizes that other competitors also tasted the tainted ingredient, including Crabtree and Margaret Brackenreid.

When Theodore Roosevelt sneaks into Canada for a hunting trip, Murdoch discovers the American President is the quarry.

As Murdoch investigates a murder with connections to vaudeville entertainers Harry and Al Jolson, Watts unravels a mystery about his own family.

Crabtree goes undercover at a chess tournament to investigate the murder of a Russian master.

Murdoch and Ogden put aside a personal matter when Nate Desmond is charged with murder.

Season Finale - An argument leads Murdoch to help a man looking for his missing wife, Crabtree contemplates his future with Nina and the Station House team works on a grisly murder.