It’s a foggy, gloomy night in London, and dangerous in the less prosperous parts of town. You can see and feel a sense of menace.

It is the story of “Sweeney Todd: The Demon Barber of Fleet Street,” which explains in its approximate three hours how Sweeney Todd, born Benjamin Barker, became the monster who stands alongside Jack the Ripper and Mr. Hyde.

Theatergoers are familiar with Stephen Sondheim’s musical, but the production through March 15 at Civic Theatre of Allentown, stands out for the way it captures its dark spirit.

This is a big show, with a cast of 10, an ensemble of 20 and an orchestra of nine conducted by Nick Conti, Music Director.

It is so large, the dialogue gets buried at a few points, but not enough to spoil the atmosphere.

Sweeney Todd (Armand Reiser) introduces himself dramatically with his self-named ballad. Reiser’s powerful voice is backed by the ensemble dressed in mid-19th century garb. Costume Designer is Rigby Maitico.

The singing is uniformly excellent, but the acting might be even better. Reiser makes Todd haunting and majestic, while resisting the impulse to chew up the scenery.

Sweeney Todd’s nemesis, Judge Turpin (Robert Trexler) is convincingly self-important and deluded, while Beadle Bamford (Tony Anthony) is more than contemptible enough.

Nina Metrick as Mrs. Lovett, maker of those famous meat pies, is comic and a bit sympathetic, making you overlook her cooking.

Mason McGowan overdoes his Italian accent as the charlatan Pirelli, just like he is supposed to.

Tobias Ragg (Melo Rodriguez) is played as an unfortunate innocent, wistfully trapped in his hellish situation.

And, in contrast, Maricel Wheatley as Johanna and Jordan Joseph as Anthony Hope are compellingly earnest as the endangered young lovers.

The set, designed by Trevor Flocco, is so amazing that the mechanical barber chair got applause when it was used. Lighting Designer is Ellen Schmoyer.

Center stage is dominated by a large boxy structure that serves as the pie shop below and the barber shop on the second level.

The house where Johanna lives is on stage left in Act One, replaced in Act Two by the underground kitchen where the pies are made. The walkway above the stage is occasionally used for incidental characters. Choreography is by Mariel Letourneau.

The play, directed by Rae Labadie, is one you will surely remember, or at least the next time that you get a shave and haircut.

“Sweeney Todd,” 7:30 p.m. Feb. 27, 28, March 6, 7, 13; 3 p.m. March 8, 15; 2 p.m., 7:30 p.m. March 14, Civic Theatre of Allentown, 527 N. 19th St., Allentown. 610-433-8903, https://civictheatre.com/