Act I

This is the story of a barber, Benjamin Barker alias Sweeney Todd who, as the story begins, returns to London after having been deported 19 years earlier, by an evil judge. After saying goodbye to his companion, Anthony who had saved him from the shipwreck, encounters Mrs. Lovett, an old acquaintance, who at first doesn't recognize him. She tells the story of the rape of Todd's wife and the incarceration of his daughter, Johanna. Only by Todd's reaction to this story does she recognize him, and they both decide to avenge the judge and the beadle.

Meanwhile, while walking the streets of London, Anthony has heard Johanna sing of her captivity and after seeing her, he falls in love.

At the same time, Todd and Mrs. Lovett, decide to lure the judge and beadle into the tonsorial parlor. The only way to do that is by making public the fact that he is the perfect barber. They find the ideal opportunity to accomplish this when they encounter the tooth-pulling barber Pirelli. In a contest of which Todd clearly is the winner, he wins the respect of the beadle. The beadle promises to attend.

After this contest Pirelli comes to Todd's tonsorial parlor. He suddenly recognizes Todd and threatens to blackmail him. The only thing left for Todd and Mrs. Lovett to do, if they want to pursue their plans is to kill Pirelli which they do. His assistant, Tobias, is left unaware of this murder, and is told that his master has suddenly disappeared.

Johanna, increasingly restless, longs for her freedom. This doesn't go unnoticed by the Judge who decides to marry her. Johanna shows some reluctance when he conveys this. He tells about this recounts to the beadle, who recommends him to have a shave. He leads the judge to Todd's parlor. At the moment Todd is ready to cut the judge's throat, Anthony comes barging in, shouting that Johanna will marry him. The judge , furious, shouts that he will lock up Johanna where neither Anthony nor any ''other vile corrupting youth'' can find her, and leaves immediately.

Frustrated by this failure Todd sings the Epiphany, in which he swears that he shall indeed get the judge, but not without practice on ''less honorable throats''. As Mrs. Lovett listens very patiently to this outburst, she has another problem on her mind: how to dispose of Pirelli's body? After Todd has finished singing, she gets a brilliant idea: why not use the body's to produce meat-pies? ''Business needs a lift'' as she sings herself. They agree to combine Todd's homicidal tendencies with Mrs. Lovett's culinary capabilities.