Beth thinks a casual encounter with a stranger at a party is a one-time thing, but he seems to have other plans. She is a college maths professor, and he turns out to be one of her students, and she is attracted enough to him that she doesn’t care. She breaks the rules and sleeps with him again and realizes she’s forgotten how wonderful such beginnings can be. No-one is getting hurt, she thinks, and no harm is being done, so she sees no reason not to have her fun. Unfortunately, Beth is also in a long-term, long-distance, very off and on relationship that suddenly turns on again. Robert is moving to her city, to live with her, and although she doesn’t want to give up sex with Ethan, she owes Robert something too. She can’t simply tell Robert they are done. One Plus Two Minus One is a tender novel of the sensuality and confusion of a beginning relationship, of the chaos and harm that secrets can cause, of avoiding choices, and making choices, and of always hoping things will work out for the best.