She’s nuts! Or is she? Director Edgar Wright has written, with Krysty Wilson-Cairns, Last Night in Soho, a posh psychological horror film that may have audience members wondering whether they are the ones who need medication.

Eloise, played by Thomasin McKenzie, leaves her bucolic country home and grandma (sixties star Rita Tushingham—and isn’t it nice to see her again?) to pursue her dreams of going to fashion school in London. She has the talent and is immediately accepted. She’s an independent young woman in her early 20s who soon leaves her school dorm room that is filled with other fashion girls and sets off on her own and rents a boarding room from sweet landlady Miss Collins (the lovely Diana Rigg of Emma Peel fame from “The Avengers” TV hit and the dishy Countess and Mrs. James Bond in 1969’s On Her Majesty’s Secret Service). Is Miss Collins really that sweet? Unbeknownst to Eloise, the room contains more baggage than her own.

The first part of this film is filled with wonderful music from so many of the sixties groups that they are too numerable to mention. Suffice it to say that the music seems the best part of the film. We hear all the great songs as Eloise (Ellie) makes the rounds of all the Soho bars. Original music is composed by Steven Price, but he must have had a hand in selecting the memorable old records that have become classics. If you remember these songs, you are dating yourself!

Ellie has an affinity for the fashions of the 60s and loves everything about that by-gone era. Even her designs look like they were originally made at the time. She becomes obsessed and thinks she sees a gal named Sandie, a gorgeous blonde aspiring singer.  She is played by one of today’s top actresses who loves challenging roles and unusual characters. Who else but the star of “The Queen’s Gambit” hit TV series, Anya Taylor-Joy. She appears to Ellie at various times, but is she real or an illusion? She dances, she cavorts, she sings, she is enmeshed in her own nightmarish world. But why? I won’t tell.

This is the turning point of the film. Director Wright fashions Ellie’s obsessions into nightmares and the light-hearted film becomes a horror show. It’s quite a shock and jarring. You wonder what kind of film is this I’m seeing? Nothing wrong with turning things to be over-the-top, but this is horror done in French Grand Guignol style with a British slant! Ellie slips into near-madness as she imagines Sandi to more or less possess and obsess her. Chills and frights galore, even as we don’t understand the reason for all the gore and shivers. Mention must be made of the imaginative and inventive cinematography of Chung-hoon Chung. Absolutely eye-dropping images created by his lenses as they peer through plate glass, fog, dazzling colors, and rain. Bravo to the man behind the camera!

Making a significant large cameo role is the silver-haired gentleman Terrence Stamp. He plays a somewhat mysterious character whose true identity is not revealed until there is a hair-raising incident. Now in his eighties, he still cuts a handsome figure.

At first you might be taken in by the lightheartedness of the beginning of the film. The music, the clubs, the kaleidoscope of colored lights, the happy young people. But when the film turns dark, it comes as an unexpected shock. It’s really a brilliant idea. The audience is hooked. Don’t take my word for it. Go see for yourself. You may dive under the seat as I did.

(Released by Focus Features, Universal Pictures and rated “R” for bloody violence, sexual content, language, brief drug material, brief graphic nudity.)