Roy Courtnay is a fictional character from the 2019 film The Good Liar, portrayed by actor Ian McKellen. He is a con artist who uses charm and deception to manipulate others for financial gain. The story follows his interactions with a wealthy widow, Betty McLeish, played by Helen Mirren, as he attempts to swindle her. As the plot unfolds, Roy's past and true intentions are revealed, leading to unexpected twists and turns. The film explores themes of trust, betrayal, and the complexities of human relationships, showcasing Roy's cunning nature and the consequences of his actions.