Nick Sandys and Michael Aaron Lindner Photo by Brett A. Beiner

Holmes explains the premise nicely. No one but Conan Doyle can see or hear Holmes and that leaves opportunity for many jokes in which Conan Doyle answers or speaks to the Holmes who is unseen by others and must come up with an alternate explanation for what he said. Witty fellow that he is, the writer comes up with some good ones. Yes, it's a device that's been done before—at least as far back as Noël Coward's Blithe Spirit, but it's executed so well here it seems fresh.

Conan Doyle and Holmes investigate the case of one George Edalji, son of the local Vicar who has emigrated from India with his English-born Caucasian wife. George is accused of mutilating horses and leaving them to bleed to death. Shades of Equus? No, this is actually taken from a real-life case in which Conan Doyle intervened. The musical's book is by Chicago actor/writer John Reeger and apart from the apparition of Holmes, is inspired by actual events. The songs are credited equally to Julie Shannon (composer-lyricist of The Christmas Schooner, the holiday musical she wrote with Reeger) and Michael Mahler, whose many musicals to receive Chicago productions include Knute Rockne All-American, Hero and October Sky. Shannon and Reeger were working on this musical until Shannon's death in 2012 and Mahler was called in to collaborate with Reeger.

The tone is one of light, yet grounded comedy. It's not farce or pastiche, and that's a good thing, considering the story touches on some very real and serious subjects. Edalji's conviction and the village's treatment of his parents are largely due to racism; Edalji is shown to be abused—even tortured—in prison; and Conan Doyle's wife is suffering from a terminal illness. The writers manage to walk this tightrope between comedy and serious stuff fairly well. They don't directly make light of the social issues addressed, but it's still a delicate balance to maintain.

That the material works well is due in large measure to the bright and snappy direction by Warner Crocker and an absolutely first-rate cast led by two most watchable actors. Conan Doyle is played by the estimable Michael Aaron Lindner, a character actor with a gorgeously booming voice who has nailed roles ranging from Sweeney Todd to Edna Turnblad. He gives Conan Doyle a nuanced mixture of impatience, humanity, and wit along with powerhouse vocals on the Shannon-Mahler score, a very tasty mix of music hall pastiche with lovely ballads that suggest the 1890s British setting while remaining pleasing to a present-day musical theatre audience. Lindner's co-star Nick Sandys is a complete delight as Holmes, delivering the witty words by Reeger, Shannon and Mahler with the driest of wit and perfect timing.

The supporting cast is a knockout all around. McKinley Carter is a lovely and lovable Louise Doyle—as respectful of her husband as British women of the era were expected to be, but clearly his intellectual equal. David Girolmo is the stern constable of Wyrley with a beautiful baritone, Matthew Keffer's bari-tenor scores on a big second act power ballad, and Christina Hall is funny and tragic as a boisterous, earthy barmaid. Anish Jethmalani and Mary Ernster as the Vicar and his wife score on the ballad, "Through a Prism," in which the two contemplate their lives in societies foreign from their homelands and the prejudices they face as an interracial couple.

Crocker and set designer Scott Davis make the smallish Mercury stage appear much bigger than it is, with walls and doorways coming in and out and actors making quick changes of costumes (designed by Robert Kuhn) and character amidst lighting designs by Yael Lubetzky that range from bright to hazily atmospheric. It's a mid-sized show that feels like a much bigger one and an altogether fun piece that ought to be around for a long time.

The Man Who Murdered Sherlock Holmes will play the Mercury Theater, 3745 N. Southport Avenue, Chicago, through March 20, 2016. For information and tickets, visit mercurytheaterchicago.com or call 773-325-1700.