I am being driven, in what appears to be an industrial zone of Vancouver, Canada, to one of the numerous nondescript warehouses that cover the area. Dull as it seems, I soon find out that this district is the new Hollywood, where many television series are filmed. The warehouse I am visiting is the home of The Magicians, the popular Syfy series about a group of twentysomethings who are inducted into the world of magic at the mysterious Brakebills academy. Partway through their education, they find their way to Fillory, a vast underworld of mythical creatures and daring quests.

The series, now in its third season, is based on Lev Grossman’s Magicians trilogy, which riffs off classic fantasy novels, especially C.S. Lewis’s Narnia adventures. Grossman, an erudite, Harvard-educated man whose day job is as a book reviewer for Time magazine (he is currently on leave, working on a novel based on the Arthurian legends), fills his novels with a dazzling array of cultural and literary references without sacrificing the excitement of youthful romance and adventure.

The TV series has wandered far afield from the novels—but their original spirit remains, and the show is now considered the jewel in the crown for Syfy. Executive producers and co-creators John McNamara and Sera Gamble have assembled an extraordinarily attractive and talented cast and shipped them all up to this warehouse. If the building is gray and seedy from the parking lot, inside is another story, one to set a fan’s heart racing. Behind double-soundproof doors, you suddenly find yourself inside the locations of the novel: the physical kids’ clubhouse, the labyrinthine Fillory library, the hold of the ship that sets sail to find the golden keys.

Today, the cast is filming a musical number, with the actors doing a credible cover of the Queen/David Bowie classic “Under Pressure.” (An exclusive clip is below.) Musical number? Since this is not a musical show, that takes some explaining.

McNamara, who also wrote and produced the highly regarded movie Trumbo, has been a Broadway musical fanatic since age 17, when he won a contest judged by Broadway legend Stephen Sondheim (with whom he remains friends to this day). Last season, to the terror of the cast’s non-singers, McNamara sneaked “One Day More” from Les Miserables into an episode. Luckily, Jade Tailor (who plays Kady Orloff-Diaz on the show) and Hale Appleman (a.k.a. Eliot Waugh) are accomplished singers, and they coached their colleagues through the experience.