Residents of a coastal town learn, with deathly consequences, the secret shared by the two mysterious women who have sought shelter at a rundown hotel.

Two mysterious women seek refuge in a run-down coastal resort. Clara (Gemma Arterton) meets lonely Noel (Daniel Mays), who provides shelter in his deserted guesthouse, Byzantium. Schoolgirl Eleanor "Ella" Webb (Saoirse Ronan) befriends Frank (Caleb Landry Jones) and tells him their lethal secret: They were born 200 years ago and survive on human blood. As knowledge of their secret spreads, their past catches up on them with deathly consequences.—Production

In the present day, lonely 16-year-old Eleanor "Ella" Webb (Saoirse Ronan) and her sexy, protective mother Clara (Gemma Arterton) have been vampires for 200 years. When a dangerous stranger hunts Clara down, she kills him, burns her apartment, and flees with Ella to a coastal town. Clara meets the lonely Noel (Daniel Mays), who is grieving the loss of his mother and is completely broken. He lodges them in his derelict Byzantium, a former hotel and bed-and-breakfast that belonged to his mother. Clara sees the chance to make money for Noel and her with a brothel. Eleanor befriends teenager Frank (Caleb Landry Jones), who has leukemia, and they fall in love. Meanwhile, two strangers are tracking Clara through the deaths of their victims. Eleanor is tired of living on the run and decides to tell their secret to Frank, but there are parts of Clara's past that she does not know.—Claudio Carvalho, Rio de Janeiro, Brazil