In 1846, Anthony Hope sails into London with the mysterious Sweeney Todd, a once-naive barber whose life and marriage was uprooted by a corrupt justice system. Todd confides in Nellie Lovett, the owner of a local meat pie shop, and the two become partners, as Todd swears revenge on those that have wronged him and decides to take up his old profession.

Marga, a well-known television presenter, organizes a dinner with old friends from boarding school to which he has not seen for 30 years. But the meeting hidden other motives. Marga projects an old super 8 film shot where they can guess the murderer of a friend by one of the dinner guests. After a night of surprises and serious accusations, the truth comes out.