I have seen “Sweeney Todd: The Demon Barber of Fleet Street” many times, but always on a large scale with high drama, elaborate sets, and special effects. The Kelrik After Dark production is quite different.

In the small theater at Unity, the audience gets up close and personal with the demon of Fleet Street, witnessing the mayhem that is often hidden or suggested in other versions.

Stephen Sondheim’s tale of murder and revenge is one of Broadway’s most intense musicals, and the intimacy at Unity heightens the intensity. The powerful, sometimes operatic music is also intense. Because the story is told in song, the fast-paced choral narration must be crisply enunciated to be understood. The Kelrik cast does a good job of getting the tale across, singing in small groups standing around the edges of the theater. The seven-member ensemble, sometimes joined by principal actors, seems much larger.

The barber of Fleet Street is an escaped convict who was wrongly convicted by a lecherous judge who coveted — and captured — the barber’s beautiful wife and infant daughter. Fifteen years later, under the new name Sweeney Todd, the barber vows revenge and his weapon is his skillful razor.

He joins forces with Mrs. Lovett, purveyor of the worst meat pies in London, and as he goes over the edge from anger to madness, they become partners in terror and her delicious pies become famous. The story is believed to be based on an old folk tale, and Hugh Wheeler’s book and Sondheim’s music turn it into a folk opera.

Larry Kaml directs the strong Kelrik cast and plays the title role. He is an excellent actor, and although his singing voice is not powerful, he convincingly creates a memorable Sweeney who is sympathetic at first, but becomes terrifying as he morphs into madness.

Lacey McNamara is terrific as Mrs. Lovett, with a fine voice, a lilting accent and great comic timing. She creates a character so charming that she is truly creepy. The duet, “A Little Priest,” when she and Sweeney agree to their grisly partnership, is performed with comic glee. It’s a highlight of the show, both funny and macabre. McNamara is also music director. She had a real task with Sondheim’s demanding songs, but the ensemble is up to it.

Judge Turpin, the object of the barber’s revenge, is melodramatically sung by Red Rahim, who plays him with manic self-loathing as he lusts after his ward, Johanna, the barber’s lost daughter. Torran Kitts is the judge’s slimy underling, Beadle Bamford. Kitts is a good character actor with a Monty Python-style comic edge to his personality.

Lester Wilson is an audience pleaser as the Italian barber, Pirelli, Sweeney Todd’s first victim. Wilson plays him with broad comedy as the two barbers have a contest for the best shave and tooth extraction. Benjamin King is funny and likable as Pirelli’s dimwitted servant Toby, who later becomes Mrs. Lovett’s helper.

Cody Pettit plays Anthony Hope, the impulsive young sailor who woos Johanna. He has some of the most lyrical songs and sings them soaringly. Danielle Dutro is properly pretty as Johanna, and she has a lovely soprano.

The beggar woman who is a key figure in Sweeney Todd’s life, but doesn’t know it, is played with flourish by Debora Schwartz. The ensemble is vital to the show. Its members are Bethany Bagg, Thea Badger, Michelle Hansen, Linda Miner, Westen Meyer, Harry Sadler and Gryphon Strom.

“Sweeney Todd” is always an adult show because of its subject matter, but this production is even more graphic than usual and definitely not for youngsters (anyone under 17 must be accom panied by a parent or guardian).

In some versions, the barber’s dastardly deeds are only alluded to. Here they are in your face, and he even addresses the audience with scary threats. But this is an ambitious production, with fine performances, packing a big musical into a small space with success.