Grace Ballard (previously Butler) is an actress and the main antagonist of Murder Mystery along with her accomplice - Juan Carlos Rivera. She is also Malcolm Quince's long lost daughter and the ex-girlfriend of Charles Cavendish. She is portrayed by Gemma Arterton.
Before the Film
Grace was born to Malcolm Quince and Madeleine LeBoutillier. After her mother died in childbirth, her father, only wanting sons, gave her away. In the future, she changed her surname to Ballard. She was also the girlfriend of Charles Cavendish before he met Suzi Nakamura.
Grace had never told anyone that she was Quince’s daughter, possibly to avoid suspicion in the mystery. She had made a deal with Juan Carlos Rivera to kill the Quinces in name of Rivera’s father who lost his legs in a car race because of Malcolm‘s safety lack. After Malcolm told everyone that Suzi would be the only one to inherit from him, Grace stormed out. Malcolm was about to sign his will until Grace turned the lights out while Malcolm’s son - Tobey - stabbed him in the chest so he and Grace could split the inheritance thanks to the French Inheritance Law. Ballard, Quince, and Rivera acted innocent, but later that night Tobey was found dead from an apparent suicide even though Grace killed him to get all of the money. Like everyone else, she blamed Nick and Audrey Spitz. She also tells Nick that Charles probably murdered Malcolm. In the hotel in Monte Carlo after the Spitzes escape from the room where Sergei was killed, the couple smuggles themselves into a room where they hear Grace and the Maharajah have sex - Grace used Vik as an alibi as she probably knew that Juan Carlos had just murdered Sergei. In Lake Como, she tries to shoot the Spitzes in a library. She attempts to shoot them again afterward, wearing a mask, this time with a blowgun but gets Suzi instead, leaving her to die later. Nick throws a plate at Grace which cracks her mask and left a mark, she escaped on a motorcycle. At Quince’s Villa, she has a shot with Charles but poisons his, knowing that he wouldn’t rest until he finds out who killed Suzi. When Nick and Audrey confront everyone, after the Maharajah suggests that Quince’s ’dead’ son that turned out to be a daughter could have changed their name, the two discover that she’s the killer after Nick remembers that her birth name is Grace Butler which translates to LeBoutillier. She does confess to being Quince’s daughter and heir to his fortune but denies being the killer. Audrey proves that Grace is the murderer after Delacroix removes her hat to reveal the mark, proving that Grace was the murderer. Grace pulls out a gun and threatens everyone, when Juan Carlos pretends to try and stop her, she knocks him down. She takes Audrey hostage but is shot in the shoulder by Nick with the Colonel’s gun and is rushed away by paramedics.