It's the 19th century and Sweeney Todd (JOHNNY DEPP) -- a.k.a. Benjamin Barker -- has arrived in London along with others, including optimistic young sailor Anthony Hope (JAMIE CAMPBELL BOWER). Fifteen years ago, Barker was a barber, happily married to Lucy (LAURA MICHELLE KELLY), when corrupt Judge Turpin (ALAN RICKMAN) set his sights on the lovely lady and thus had Benjamin arrested and sent off to prison.
Now seeking revenge, Sweeney sets up shop above the restaurant where his former landlady, Mrs. Lovett (HELENA BONHAM CARTER), sells the worst meat pies in town. Learning that Turpin has his now grown-up daughter, Johanna (JAYNE WISENER), locked away in his manor, Sweeney's goal is to lure the judge into his barbershop and slit his throat with one of his trusty straight razors.
He gets the chance when Turpin's henchman, Beadle Bamford (TIMOTHY SPALL), observes Sweeney defeat flamboyant barber Adolfo Pirelli (SACHA BARON COHEN) in a shaving contest, and thus refers his boss to the talented man with a sharp blade. The barber misses his chance, however, when Turpin realizes that Sweeney knows Anthony who's recently been wooing Johanna, unbeknownst to her father.
The judge gets away, and thus Sweeney takes out his anger on others, slitting their throats. With the price of quality meat prohibitively high, Mrs. Lovett comes up with the idea of using his victims as her new ingredient, and it's not long before Pirelli's former assistant, the young Tobias Ragg (ED SANDERS), is helping her serve her newly delicious pies to the unsuspecting masses.
With Turpin determined to marry the horrified Johanna, Sweeney waits for his next chance to get the judge in his barber's chair to get his revenge on him.