Grace suffers from OCD, which breeds her love of inventor Nikola Tesla and causes her to fixate on numbers, attaching symbolic significance to things as seemingly mundane as the number of steps to her local coffee shop. But it’s at this coffee shop that she meets Seamus, a cute Irishman who disrupts her routine and shakes up her life of self-isolation. As romance blossoms, so does Grace’s uneasiness about making herself vulnerable to another person. Australian author Toni Jordan explores her heroine’s psychology with depth, revealing surprising hidden traumas from Grace’s past which are always threatening to bubble to the surface. Addition is no cookie-cutter romance—it’s like chick lit with a twist of grit.