The Invisible Detective is a British middle-grade mystery/horror series by Justin Richards that follows two boys named Arthur Drake. The story begins in 2003 when one Arthur is stunned to discover that another Arthur Drake (who is mostly called Art and receives much more page-time than the present-day Arthur) was involved in a series of Gaslamp Fantasy adventures in 1937 as a member of the Cannoniers, a group of Baker Street Regulars for reclusive detective Brandon Lake. However, Lake is an Invented Individual, and the kids solve the cases themselves while getting involved in some increasingly bizarre, dangerous, and sometimes paranormal adventures that inspire the present-day Arthur to undertake adventures of his own.
Books:
- The Paranormal Puppet Show/
Double Life - Shadow Beast
- Ghost Soldiers
- Killing Time
- Faces of Evil
- Web of Anubis
- Stage Fright
- Legion of the Dead
Tropes in the novels:
- Bank Robbery: Shadow Beast involves the Cannoniers trying to solve a bank robbery committed by a man who controls a frightening monster.
- Chekhov's Gunman: Two in The Paranormal Puppet Show.
- Arthur Drake's grandfather is mentioned or seen in several chapters (mostly discussing how he has just been put in a retirement home) before it turns out that he is Art Drake from 1937, whose cases Arthur has been reading about as the framing device.
- Arthur's classmate Sarah appears for 2 pages as a new member of the computer club, who Arthur assumes is one of the many girls who joined solely because of their crush on the new teacher. Two books later, it turns out that she is the operator of the website about the Invisible Detective that Arthur has been visiting throughout the series, and the two become best friends.
- Dramatic Dislocation: Flinch can dislocate her joints at will to squeeze through tight spaces.
- Escaped from the Lab: Ghost Soldiers reveals that the eponymous creature from The Shadow Beast was one of several first generation mutated slave soldiers (subsequent Unwitting Test Subjects are forced to become far more aggressive) who escaped from their Mad Scientist creators.
- Fish out of Temporal Water: One book sees Art and Arthur sent into each others' time periods by the mysterious lodestone.
- It's Personal: The present-day plot of Killing Time features a crew of zombie pirates who died in a shipwreck going on a Roaring Rampage of Revenge. However, contrary to initial impressions, they aren't after the descendants of the villagers who deliberately wrecked their ship to claim the salvage, with the captain saying that "they had as much right to trick us onto the rocks as we had to attack merchantmen and raid coastal ports." Their real target is a Really 700 Years Old surviving pirate who betrayed his friends (although he argues he had justification) and stole a treasure that included the mystic watch that has kept him alive and could have saved the others.
- Late-Arrival Spoiler: Art and Arthur Drake being grandfather and grandson and the Cannoniers' elderly friend Charlie being the Earl of Fotherington are big twists in the first book but are well-established for the rest of the series.
- Living Lie Detector: Being part of an abusive family has made Meg an expert at noticing liars' tells.
- No One Sees the Boss: Private Detective Brandon Lake only ever talks to people besides his Baker Street Regulars from behind a silhouette-outlining curtain and recruits Charles, the Earl of Frotherington to be his representative in meeting people who want regular updates from a respectable adult about his cases. Lake is an Invented Individual, with one of "his" regulars (Art) providing the silhouette and voice while wearing oversized clothes, while another (Jonny) uses a fishing rod to send messages from the others down to Art whenever he doesn't know what to say to Lake's visitors.
- Red Shirt Army: In the climax of Ghost Soldiers, the eponymous monsters end up in a running gunfight with about a dozen human soldiers who encounter and end up protecting the four young detectives. Only three of the heroes' protectors survive the fight, although the human soldiers do kill most of the Ghost Soldiers.
- Those Wacky Nazis: Dr. Bessemer, a Bavarian puppeteer from the first book, is a Nazi agent out to kill the Duke of York and replace him with a robot before the Duke of York becomes king once his brother, King Edward VIII, abdicates.
