The company, representing citizens of London, drop a body bag into a rough coffin. As they sing, Sweeney Todd rises from the coffin as though summoned by their song (“The Ballad of Sweeney Todd”), and introduces the play, set some months before the burial. The company appear throughout the show as a Greek chorus to comment on the action of the play.
The year is 1846, in which the young sailor Anthony Hope has recently rescued Sweeney Todd at sea, and the two arrive back in London. On land, Todd’s grim mood is worsened by a half-mad Beggar Woman who sexually solicits both men, and appears to recognize Todd (“No Place Like London”). Before the two part, Todd discourages Anthony’s innocence by describing a naïve barber (himself), his wife, and the judge who exiled him to pursue her (“The Barber and His Wife”). Todd soon enters a meat pie shop on Fleet Street, where the shop’s proprietress, Mrs. Nellie Lovett, laments about her incompetent pie-making and the the difficult economic times (“Worst Pies in London”). When Todd asks about her unoccupied upstairs apartment, she reveals that its tenant, the barber, Benjamin Barker, was transported to Australia for life on false charges by the corrupt Judge Turpin because of the Judge’s lust for Barker’s wife, Lucie; whereafter the Judge and his loyal cohort, Beadle Bamford, lured Lucie to the Judge’s home and raped her (“Poor Thing”). Todd’s reaction to this narrative confirms Mrs. Lovett’s suspicions that he is indeed Benjamin Barker; and she tells Todd that his wife poisoned herself and that their then infant daughter, Johanna, became a ward of the Judge. When Todd swears revenge on the Judge and Beadle, Mrs. Lovett reveals Todd’s old collection of sterling silver razors, with which (she claims) he can resume his former trade above her shop. Todd accepts (“My Friends” and “The Ballad of Sweeney Todd – Reprise”).
Meanwhile, Anthony notices an exquisite blonde girl singing to the birds sold outside her window (“Green Finch and Linnet Bird”), and the Beggar Woman tells Anthony that the girl is Johanna, Judge Turpin’s ward. Unaware that Johanna is his friend Todd’s daughter, Anthony is immediately enamored (“Ah, Miss”) and pledges to woo her; but the Judge and the Beadle frighten him into leaving, and Anthony swears to seize her from them (“Johanna”).
In the crowded marketplace, faux-Italian barber Adolfo Pirelli and his simple-minded assistant, Tobias Ragg, pitch a cure-all for hair loss (“Pirelli’s Miracle Elixir”); whereupon Todd, after exposing the elixir as a hoax, challenges Pirelli to a shaving and tooth-pulling competition, which he wins easily (“The Contest”), and invites the impressed Beadle to a complimentary shave (“The Ballad of Sweeney Todd – Reprise 2”).
Several days later, Judge Turpin mortifies his sinful flesh by flagellation, and resolves to marry Johanna himself. (“Johanna/Mea Culpa”). Todd grows frustrated waiting for the Beadle’s arrival, despite Mrs. Lovett’s attempts to calm him (“Wait”). Anthony tells Todd of his plan to ask Johanna to elope with him, and requests to use Todd’s barbershop as a safe-house for the girl; and Todd, eager to be reunited with his daughter, agrees. When Anthony leaves, Pirelli and Tobias visit the shop, and Mrs. Lovett takes Toby downstairs for a pie. Alone with Todd, Pirelli reveals that his real name is Daniel O’Higgins and recounts having served as an assistant to Todd fifteen years ago. When O’Higgins attempts to blackmail his former employer, Todd knocks him unconscious and conceals him in a trunk. Having distracted Tobias with a promise of another pie and some gin, Todd cuts O’Higgins’ throat (“Pirelli’s Death” and “The Ballad of Sweeney Todd – Reprise 3”). Johanna and Anthony plan to elope (“Kiss Me”), while the Beadle recommends Todd’s services to the Judge, in order to improve his appearance for better winning Johanna’s affections (“Ladies in Their Sensitivities”).
Mrs. Lovett, having learned of Pirelli’s murder, is panicked until she learns of the blackmail attempt, after which she seizes Pirelli’s coin purse. She and Todd are planning to dispose of the body when the Judge enters, and Todd admits him; lulling the Judge into relaxation and engaging him in a conversation (“Pretty Women”). Before Todd can kill the Judge, Anthony enters to tell Todd his and Johanna’s plans, accidentally informing the Judge, who storms out, vowing never to return. Todd drives Anthony away before descending into madness, in which he vows to punish the rich and corrupt, and relieve the poor of their misery, by killing his clients (“Epiphany”), and Mrs. Lovett suggests that they use the flesh of Todd’s victims (including Pirelli) in her meat pies (“A Little Priest”).
Several weeks later, Mrs. Lovett’s pie shop has become a thriving business, and Toby is working for Lovett as a waiter (“God, That’s Good!”). Todd and Mrs. Lovett acquire a specially-designed mechanical barber’s chair that allows Todd to kill his clients and send their bodies through a chute into the pie shop’s basement bakehouse for Mrs. Lovett to cook. Todd has accustomed himself to having lost Johanna, and spends his time cutting his customers’ throats, while Anthony searches the city for her and the Beggar Woman shrieks against the foul-smelling smoke arising from Mrs. Lovett’s bakehouse (“Johanna–Quartet”). Anthony finds Johanna when he hears her singing from an insane asylum, but he is chased away by the Beadle.
After a day of hard work, Mrs. Lovett tries to allure Todd with retirement by the seaside (“By the Sea”); but he remains fixed on his revenge. Anthony begs Todd for help to free Johanna from the madhouse, and Todd devises a plan to rescue her by having Anthony pose as a wigmaker intent on purchasing inmates’ hair (“Wigmaker Sequence” and “The Ballad… – Reprise 4”). When Anthony has gone, Todd sends a secret letter to notify the Judge of Anthony’s plot, hoping to lure the Judge to his shop. The contents of the letter are sung aloud by a quintet from the company (“The Letter”).
In the pie shop, Toby expresses suspicions against Todd and his own desire to protect Mrs. Lovett (“Not While I’m Around”). When he recognizes Pirelli’s coin purse in Mrs. Lovett’s possession, she distracts him by showing him the bakehouse, instructing him how to work the meat grinder and the oven, and then locking him alone in the basement. Upstairs, she encounters Beadle Bamford at her harmonium, commissioned by neighbours to investigate the strange smoke emitted from the pie shop’s chimney. Mrs. Lovett stalls the Beadle until Todd offers the Beadle his promised “free shave”; whereupon Mrs. Lovett loudly plays her harmonium to cover the screams of the Beadle’s demise above (“Parlour Songs”). In the bakehouse, Toby discovers a hair and a human finger in a pie just as the Beadle’s fresh corpse tumbles into the basement driving him mad. Above, Mrs. Lovett informs Todd that Toby has discovered their secret, and they resolve to kill him.
Anthony arrives at the asylum to rescue Johanna; but Mr. Jonas Fogg, the owner of the asylum, attempts to stop them. When Anthony is unable to kill Fogg, Johanna does so instead, and they escape. The asylum’s inmates run onto the streets, ecstatically proclaiming the end of the world, while Todd and Mrs. Lovett hunt for Toby and the Beggar Woman calls on the Beadle to beware of Mrs. Lovett (“City on Fire/Searching”).
Anthony and Johanna, who is now disguised in a sailor’s uniform, arrive to find Todd’s shop empty. Anthony and Johanna reaffirm their love (“Ah Miss, Reprise”) and then he leaves to find a coach for them both to escape in. Left alone, Johanna hears the Beggar Woman calling for the Beadle and hides before the frenzied woman enters the barbershop. The Beggar Woman seems to recognize the room; but before she can make sense of it, Todd arrives and slits her throat, sending her down the chute before the Judge enters (“Beggar Woman’s Lullaby”). Todd assures the Judge that Johanna is repentant and the Judge asks for a face massage and some cologne before reuniting with her. Once he has the Judge in his chair, Todd soothes him first and then suddenly mocks him; whereupon, the Judge recognizes Benjamin Barker just before Todd kills him (“The Judge’s Return”). Todd then leaves to find Tobias, but catches Johanna hiding in his tonsorial parlour and, not recognizing her in the sailor’s uniform, he nearly slits her throat before Mrs. Lovett shrieks from the bakehouse below, providing a distraction for Johanna to escape.
In the bakehouse, Mrs. Lovett panics while struggling with the wounded Judge, who claws at her before finally dying. She attempts to drag the Beggar Woman’s body into the oven, but Todd arrives before she can do so. When the light from the oven falls upon the dead woman’s face, Todd realises in horror that she is his wife Lucie. Under pressure, Mrs. Lovett confesses she concealed Lucie’s survival from Todd to make him available to herself; and Todd feigns forgiveness and dances with her until she is in front of the oven, into which he throws her and slams the door. Todd then embraces the dead Lucie and recalls his background story. Toby, quite mad with his hair now white from shock and babbling nursery rhymes to himself, picks up Todd’s fallen razor, and slits Todd’s throat. As Anthony, Johanna, and a Peeler break into the bakehouse, Todd falls dead and Toby drops the razor, heedless of the others, while absentmindedly turning the meat grinder (“Final Scene”) smoothly, smoothly.
The company recites “The Ballad of Sweeney Todd”, and the ghosts of Todd and Mrs. Lovett conclude that Todd’s revenge was efficient. The company exits, with Todd and Mrs. Lovett being the last. Todd pauses at the large iron door at the back of the stage to look at Mrs. Lovett before slamming the door in the audience’s face.