The Irregulars is an upcoming British-American tv series, set in the Sherlock Holmes universe. The plot focuses on a group of "high-functioning sociopaths" who work for Dr. Watson and try to solve supernatural crimes. The teaser contains all sorts of mystical objects: a magical newspaper, like the ones in Harry Potter, which reports a crime and the tarot cards seen later are similar to that of Dr. Facilier from Disney's Princess and the Frog (2009).
As its name suggests, the show was inspired by the Baker Street Irregulars, fictional characters created by Sir Arthur Conan Doyle. They were street boys hired by Sherlock to run errands and find out information. However, not many people know about them as they only appeared in two novels and a short story. So this spin-off might do some justice for these characters.
Tom Bidwell, the creator of the show, revealed that this has been his "dream project and oldest idea", pitching it for 10 years until Netflix decided to give it a go. In a BBC interview from 2018, he explained the reason behind his idea: "What if Sherlock was a drug addict and a delinquent and the kids solve the whole case whilst he takes credit?" If we think about it, the interpretation is not so absurd: it is quite impossible for a person to have such a powerful sense of logic and deduction without the help of supernatural forces.
The spin-off could present two different perspectives. The first one would be to remain true to Doyle's storyline, solving and explaining the famous cases (A Study in Scarlet, The Hound of the Baskervilles, etc.) from a supernatural point of view. The other way would be to create new crimes and completely reimagine the stories.
It remains to be seen if the show will live up to the expectations created by the association with the Sherlock Holmes universe. But either way, The Irregulars will probably be a nice addition to the list of supernatural detective shows, alongside Lucifer, Grimm, and Supernatural.