Season 4 consists of 13 episodes, maintaining the show's established format of blending historical fiction with police procedural elements. Set in Toronto at the turn of the 20th century, the season follows Detective William Murdoch (Yannick Bisson), a pioneer of forensic science.

XviD is an open-source implementation of the MPEG-4 video coding standard. It was the primary competitor to DivX during the era before High-Definition (HD) file sharing became standard.