|Air date||December 5, 2016|
|Written by||Simon McNabb and Peter Mitchell|
|Directed by||Cal Coons|
|Recurring||Peter Stebbings as James Pendrick|
|Previous||Weekend at Murdoch's|
|Next||The Devil Inside|
Murdoch strives to apprehend a lecherous costumed criminal known as The Lurker.
Inspector Brackenreid returns after seeing some exciting things at the World's Fair in St. Louis, making him wonder if there’s more he missed.
Murdoch and Crabtree inform the Inspector that The Lurker has resurfaced. His petty theft, destruction of property and tempting of women began shorty before the Inspector left for St. Louis. Murdoch points out, like with any criminal, the severity of his crime could increase. "Put the kettle on, Crabtree."
Every evening there is a Lurker incident: After his thwarted attack of Lydia Hall who stabs him with a hat pin, he burgles the Brackenreid's home, scaring Margaret and stealing Pendrick's swords.
When popular Gerard Waldkirch, known by all as the Sausage King, is found dead by his toppled sausage stand - the cause of death a very deep knife wound - witnesses can not give much of a description, but it was the Lurker. Crabtree reports that they saw a man cloaked in darkness who snarled like an animal – the Lurker has moved up to murder.
- Realizing that "the world is a bloody marvelous place", Thomas Brackenreid feels his life is half over and he's barely scratched its surface. In other words, Brackenreid is having a midlife crisis.
- Inspector Brackenreid and James Pendrick bonded at the World's Fair in St. Louis and Murdoch feels left out.
- Before escaping Station House No. 4, The Lurker (aka James Pendrick) gives Dr. Julia Ogden a long swooping kiss, afterwards Julia calmly states, "I've had better."
- Brackenreid has been grabbed by wanderlust. No longer content being a station house copper, Thomas goes off on a quest with Pendrick in pursuit of Ashmi, who’s stolen the inventor’s formula for the fountain of youth.
- Inspector Brackenreid returns to Station House No. 4 as a world champion with an Olympic gold metal.
- Fourth time the Hot Sausages Stand appears, the first was in Journey to the Centre of Toronto, the second was in From Buffalo With Love and the third was in Concocting A Killer.
- The return of James Pendrick with Ashmi a new female assistant– again and his luck with beautiful women has not changed.
- At The Tipsy Ferret, Brackenreid's nickname 'Tommy-Two-Cakes' becomes 'Ten-Tankard-Tommy'.
- Murdoch mentions flying over the falls with Pendrick in Murdoch Air.
- There is a Lurker routine performing at The Star Room, mayhem ensue when the real Lurker appears onstage. Nina smashes a bottle over his head, stopping him in his tracks.
- Julia notes the déjà vu of suspecting James Pendrick as the killer when she examines his samurai swords and points out that he is usually exonerated.
- Pendrick invents a powerful "energy drink" with guarana that he calls 'Jumper' (see Pendrimine).
- The Burt Lightman modern nude painting (of Sally Pendrick) from This One Goes to Eleven (in the Pendricks first appearance), which Murdoch misinterprets as a landscape, reappears concealing Pendrick's wall safety vault.
- Gazette Reporter Louise Cherry returns to interview Crabtree on The Lurker.
- George receives a 'Dear John' letter from Nina.
- The Louisiana Purchase Exhibition was informally called the St. Louis World's Fair, an international exhibition held in St. Louis, Missouri, USA, from April to December, 1904.
- Oblique reference by Brackenreid to Ota Benga, a captured Mbuti pygmy known for being featured in an anthropology exhibit at the Louisiana Purchase Exposition in St. Louis, Missouri in 1904, and in a human zoo exhibit in 1906 at the Bronx Zoo, who did escape the Fair to wander about as a free man until he was recaptured.
- The steel nickel (iron) battery, under the "Exide" brand was originally developed in 1901 by Thomas Edison.
- The original Ferris Wheel by George Washington Gale Ferris Jr. was a landmark for the 1893 World's Columbian Exposition in Chicago. Rebuilt on Chicago's North Side and operated there until 1904, when it was dismantled and transported by rail to the 1904 World's Fair.
- Antique Japanese Katana Swords, weapons used by the Samurai during the Muromachi Period.
- Allusion to Robert Louis Stevenson's Strange Case of Dr Jekyll and Mr Hyde first published in 1886.
- The Fountain of Youth is a spring that supposedly restores the youth of anyone who drinks or bathes in its waters. Tales of such a mythical fountain have been recounted around the globe for thousands of years.
- About the Murdochian take on Strange Case of Dr Jekyll and Mr Hyde , MM writer Simon McNabb admits, "...the notion of a Jekyll and Hyde story was one that has sort of wandered in and out of the writers’ room over and over again".
- This episode originally aired on Thomas Craig's birthday.
- This is the Season 10 episode (mid season) before CBC's holiday special Once Upon a Murdoch Christmas.
- The title is a possible play on Warren Zevon's song "Excitable Boy".
- The first recorded use of the proverb "An apple a day keeps the doctor away" was in the 1860s in Wales, UK. The original wording of the saying was "Eat an apple on going to bed, and you'll keep the doctor from earning his bread." The current phrasing was first used in print in 1922.
Mouna Traoré as Rebecca James
Kristian Bruun as Constable Slugger Jackson
Arwen Humphreys as Margaret Brackenreid
Peter Stebbings as James Pendrick
Erin Agostino as Nina Bloom
Bea Santos as Louise Cherry
Katy Breier as Lydia Hall
Glenda Braganza as Ashmi
Andrew Di Rosa as Peregrine Fawkes
Teagan Vincze as Estephanie
Katriina Isberg as Dr. Karlson
Nathan Hoppe as Constable McNabb