After dropping an ominous teaser for it in February, Netflix has now released a full trailer for its upcoming series The Irregulars. It’s part of the streaming channel’s Sherlock Holmes cinematic universe (no that’s not a thing, but it could be!) after last year’s charming Enola Holmes series, which told the story of Sherlock’s younger sister, based on the novels by Nancy Springer (although Arthur Conan Doyle’s estate has sued Netflix for that series’ portrayal of Sherlock as too emotional).

The Irregulars is loosely based on the street urchin gang called the Baker Street Irregulars, who appeared in several of Arthur Conan Doyle’s Sherlock Holmes stories. In the books, the Irregulars are sort of like confidential informants for Holmes and Dr. Watson, giving them info from the streets and helping them solve cases in Victorian London.

The Netflix production, however, casts Sherlock and his sidekick in a decidedly sinister light. It also puts the supernatural elements that typically lurk around the edges of Holmes stories front and center, with Jessie (Darci Shaw), a girl who “can see things normal people cannot,” like perhaps dead people, and something called a “Rip” (capital R, says the closed captioning) in “the barrier between our world and the next,” which sounds very not good. The Irregulars — Jessie, Bea (Thaddea Graham), Billy (Jojo Macari), Spike (McKell David), and Leo (Harrison Osterfield) — have to close the Rip, or everyone’s doomed.

The series director is Tom Bidwell, who has said this project has been a dream of his for more than a decade. Judging by the trailer, Sherlock (Henry Lloyd-Hughes) himself is a minor character — he only appears in five of the series’ eight episodes — and Dr. Watson (Royce Pierreson) as a baddie is a fun twist. The Irregulars debuts on Netflix March 26th.