Miss Hinchcliffe is a tall woman, and has a "short man-like crop" of hair, and a "weather-beaten countenance".
She and Miss Murgatroyd live at Boulders which they own as a farm, they guests at Little Paddocks when the shooting takes place. They give their statements to Inspector Craddock, with Murgatroyd tripping over her words. They are also at Dora Bunner's Birthday Party.
Miss Hinchcliffe and Miss Murgatroyd attempt to reenact the events of the shooting at Little Paddocks in their own home. Miss Hinchcliffe realises that the door of the drawing room at Little Paddocks does not stay open, and that it would have been difficult for Rudi Scherz to hold the door open while holding a flashlight and a revolver. She comes to the conclusion that someone might have held the door open for him.
Miss Hinchcliffe later realises that Miss Murgatroyd was standing behind the door of the drawing room at Little Paddocks on the day of the shooting, and therefore was the only one who was not dazzled by the flashlight, and could see who else was in the room. She tries to get Miss Murgatroyd to remember who was not in the room when the shots were fired. However, before Miss Murgatroyd can tell her who wasn't in the room, Miss Hinchcliffe receives a telephone call informing her that their dog, Cutie, is at the station, and she leaves to pick it up. While she is away, Miss Murgatroyd is strangled to death.
Solution Spoilers Ahead
Hinchcliffe, picks up Miss Marple while driving back, they find Murgatroyd dead and Hinchcliffe vows that "she" is going to pay. The reason was that Murgatroyd said one of the female guests was missing when she saw the light across the room. At Little Paddocks she is witness to Charlotte Blacklock exposed as the killer.
1985 BBC Version
In the BBC 1985 adaptation of the novel which formed part of the Miss Marple series, Miss Hincliffe is played by Paola Dionisotti. In this adaptation, she mentions that she was in the ARP during the war. This detail is not mentioned in the novel or the 2005 version. Like in the novel, Miss Hinchcliffe and Miss Murgatroyd attempt to reenact the events of the shooting at their own home, and realise that it would have been difficult for Rudi Scherz to hold the door open while also holding a flashlight and a revolver. Miss Hinchcliffe also realises that Miss Murgatroyd was behind the door, and could see who was not in the room when the shot was fired. However, before Miss Murgatroyd can tell her who it was, she has to leave to pick up the dog, Cutie, from the station. When Blacklock is arrested, Hinchcliffe enters the kitchen as well Blacklock apologises to her, she is held back before she attempts to attack Blacklock. This production was the first to suggest that Hinchcliffe and Murgatroyd were lesbians.
2005 ITV Version
In the ITV 2005 adaptation of the novel, Hinchcliffe is played by Frances Barber. In this adaptation, her first name is Lizzie. This name does not occur in the other versions. Unlike the novel and the 1985 adaptation, she is at Boulders when Miss Murgatroyd is killed, but she does not witness it because she is attending to the pigs. Also added to this version she attacks Blacklock, after the solution is revealed ripping off the pearls she wears to reveal her scar. The dog, Cutie, does not appear in this adaptation. In this version it's clearly that Hinchcliffe and Murgatroyd are lovers.