Sherri Edelen as Mrs. Lovett in ‘Sweeney Todd.’

Few shows walk the line quite as successfully as Sweeney Todd. Whether the line be between horror and absurdity, good and bad taste, gore and slapstick, Sweeney is there to push the boundaries. And Signature Theatre’s gleefully bloody, winking but impassioned production is firmly in that spirit.

Courtesy of Tim Burton and Johnny Depp (hearing the tweens in Signature’s audience Wednesday debate the merits of the musical versus the movie was amusing; glad to hear the play come out on top), the story of Sweeney is even more well-known at this point, and it’s not an obscure show to begin with. Barber meets girl, barber gets banished on trumped-up charges, wife poisons herself, barber returns to avenge his wife’s death, murder ensues, bodies are eaten – in pie form, of course. The show has a wicked sense of humor, from bemused lyrics (“They went to their maker impeccably shaved”) to songs where context is key.

Take the plaintive ballad “Johanna.” First it’s a desperate love song sung between a man and his captive love — the lyrics are plaintive, but also veer into stalker territory (“Do they think that walls could hide you?/Even now, I’m at your window/I am in the dark beside you”). The song’s reprise, sung by a variety of players in the show, veers even farther away from its sweet roots, with Sweeney Todd’s victims percussively falling to the depths of his pie-shop basement as the song meanders. Cleverness aside, the show also produces some of Sondheim’s most achingly beautiful melodies, such as the lilting duet “Pretty Women.”