Continuity mistake: A henchman places a briefcase up-side down on a bench, opens the locks and starts to open the briefcase with the locks above the lid latches which are flipped open toward the floor. Instantly the briefcase is right-side up with the locks down and the lid latches up. (00:26:11)
Factual error: Enid, the telegraph operator, exclaims that "He is sending an SOS." However, in the 19th century, distress calls did not include the letters "SOS," It was not until the early 20th Century that SOS was chosen as the international distress call.
Factual error: In the opening sequence when Maddie is supposedly driving from Michigan through Ohio and back to Pennsylvania, you can very briefly spot the reflection of a "TD Canada Trust" in the car window. This is because the show is actually shot in Vancouver. In the United States the company is simply known as "TD Bank", which doesn't operate any branches in either Michigan or Ohio. (00:01:55)
Other mistake: Jack follows J. Edison Nash to a wine warehouse and watches as Nash punches numbers on a keypad in order to gain entrance to a private room. Nash punches the 6 and a beep is heard. He then punches the 8 and another beep is heard. During a close-up of Jack, four more beeps are heard, for a total of six. Jack says the number out loud - 862, which is only three digits.
Visible crew/equipment: After leaving her husband at train station, Harriet takes a cab to meet a man at a cabin. After a few mins, she takes the man's car to go home. As she drives away, there's a reflection of a man, in suit with glasses (possibly the director) standing offscreen. (00:05:20)
Factual error: The show starts in 1901 with a woman constable working for the Metropolitan Police Service (Scotland Yard). However women didn't join the Metropolitan Police until 1919 (which is also when the first woman's police uniform was created). Prior to that, women volunteered in the Women's Police Service, but that wasn't formed until 1914.