Professional violinist Anna Sun became internet famous when a YouTube video of her went viral and now all she hears are the imperfections and mistakes as she struggles to master a composition written specifically for her. Her family practice tough love and she has always laboured under the weight of their judgements and expectations. When Anna’s long-term boyfriend, Julian, one of the things about her life that her parents do actually approve of, announces his wish to try out an open relationship in the belief that Anna’s won’t actually experiment, her friends encourage her to give it a go. Deciding to try a one-night stand in the hope of overcoming her sexual inhibitions she joins a dating app and meets tattooed and shaven-headed biker Quan Diep, who comes with his own emotional scars. After her therapist suggests that she might be on the autism spectrum and Anna finally recognises herself and her struggles in the literature, she is dismissed by her bossy older sister who thinks she is simply looking for an excuse to justify being different. Despite three consecutive date nights with Quan not going to plan he accepts Anna in a way that nobody else does and she is able to shed the exhausting masking that has led her to burnout point. Deciding to overcome their intimacy issues together after making an emotional connection and finding acceptance with each other, The Heart Principle features multiple graphic, albeit very well-written, sex scenes. Life gets even more complicated for Anna when he elderly father falls ill and her older sister makes the decision for the family to care for him at home.