In 1846, Benjamin Barker, a barber, arrives in London, accompanied by young sailor Anthony Hope. A flashback reveals that sixteen years prior, Benjamin was falsely convicted and exiled to Australia by the corrupt Judge Turpin, who lusted after Benjamin's wife, Lucy ("No Place Like London"). Benjamin adopts the alias "Sweeney Todd" and returns to his old barber shop on Fleet Street, situated above Nellie Lovett's failing meat pie shop ("The Worst Pies in London"). Recognising Benjamin, Mrs. Lovett tells him that once he was exiled, Turpin raped Lucy at a masquerade ball in his home and drove her to suicide before adopting the couple's daughter, Johanna, as his ward ("Poor Thing"). Todd vows revenge and re-opens his barbershop after Mrs. Lovett, who is unrequitedly in love with him, presents him with his old straight razors ("My Friends").
Anthony becomes enamored with Johanna after seeing her sing by a window above the street ("Green Finch and Linnet Bird"). A beggar woman warns him about Judge Turpin ("Alms! Alms!"), who invites Anthony into his house before setting his henchman and personal bailiff, Beadle Bamford, upon him. The Beadle throws Anthony into the street and beats him with a cane, but Anthony vows to return and rescue Johanna ("Johanna").
Rival barber and snake oil salesman Adolfo Pirelli is publicly humiliated by Todd at a shaving contest in front of Bamford ("Pirelli's Miracle Elixir/The Contest"). At his barbershop, Todd is distressed that Turpin has not yet arrived after The Beadle promised he would visit before the end of the week. Mrs. Lovett encourages him to calm down and come up with a plan ("Wait").
Pirelli visits Todd and reveals that he recognized him by his distinctive straight razors, and attempts to blackmail Todd using the knowledge of his former identity. Todd panics and kills Pirelli, hiding his body in a chest. Mrs. Lovett is shocked but accepts Todd's justifications, having grown emotionally attached to Pirelli's downtrodden assistant Tobias "Toby" Ragg, whom she adopts as a son.
Intent on marrying Johanna, Judge Turpin visits Todd's shop for a shave at Bamford's recommendation ("Ladies in their Sensitivities"). They sing a duet ("Pretty Women") but before Todd can kill Turpin, Anthony bursts in and inadvertently reveals his intentions on eloping with Johanna. Judge Turpin angrily storms out and has Johanna committed to an asylum, offering her her freedom in exchange for her hand in marriage. Todd laments that Johanna is gone forever, and vows revenge on all of London for wronging him ("Epiphany").
Trying to figure out what to do with Pirelli's corpse, Mrs. Lovett suggests that they bake him in a pie. Todd and Mrs. Lovett decide that Todd will kill his customers and Mrs. Lovett will bake their bodies into meat pies to feed to the public ("A Little Priest"). Todd rigs his barber chair with a mechanism to drop his victims' corpses through a trapdoor and into her basement bakery, where she bakes them into pies. Meanwhile, Anthony continues to search for Johanna, Todd laments his missing daughter, and the beggar woman tries to warn the public about Mrs. Lovett's pies ("Johanna – Reprise").
With both their businesses prospering and customers raving about the pies while unaware of their contents ("God, That's Good!"), Mrs. Lovett tells an uninterested Todd of her hopes to marry him and retire ("By the Sea"). Anthony poses as a wig maker in order to rescue Johanna from the asylum, planning on hiding her in Todd's barbershop. Toby becomes wary of Todd and tells Mrs. Lovett of his suspicions, vowing to protect her ("Not While I'm Around"). After he discovers Pirelli's purse in her possession, Mrs. Lovett locks him in the basement and intends on killing him.
The Beadle arrives to inspect reports of the stench from the chimney, but is tricked and murdered by Todd. Toby finds a toe in a pie in the basement, then finds the piles of butchered corpses and, finally, witnesses the Beadle's body fall through the trapdoor into the basement. Mrs. Lovett informs Todd of Toby's suspicions and the pair search for the boy after he escapes into the sewers. Meanwhile, Anthony brings Johanna, disguised as a boy, into the shop and has her wait there while he leaves to find Todd.
The beggar woman enters the shop looking for Bamford and Johanna hides in the chest. The woman recognizes Todd, but upon hearing Turpin approaching, Todd kills her and drops her through the trapdoor. Todd explains to Turpin that Johanna had repented and is returning back to him, offering a free shave in the meantime. Todd reveals himself as Benjamin Barker, before slashing Turpin's throat and dropping him into the basement.
Todd discovers Johanna but does not recognize her, preparing to kill her as well. Meanwhile, the dying Judge Turpin clutches at Mrs. Lovett's dress, causing her to scream and distract Todd; he allows Johanna to flee the shop and hurries to the bakehouse to finish Turpin off. He then recognizes the beggar woman as his wife Lucy and Mrs. Lovett admits that she lied to him about her suicide. He feigns forgiveness and they waltz together, before he kills her by throwing her into the oven. Toby emerges from the sewer and grabs Todd's razor as the latter mourns Lucy. Todd allows Toby to slit his throat, and Toby walks away as Todd bleeds to his death in the basement, holding Lucy's body ("Finale").
Tim Burton first saw Stephen Sondheim's 1979 stage musical, Sweeney Todd: The Demon Barber of Fleet Street, as a CalArts student in London in 1980. Burton recalled his experience of seeing the show, saying, "I was still a student, I didn't know if I would be making movies or working in a restaurant, I had no idea what I would be doing. I just wandered into the theatre and it just blew me away because I'd never really seen anything that had the mixture of all those elements. I actually went three nights in a row because I loved it so much."
