Lilly Stone is a brilliant, perfectionist architect whose life ends abruptly in a tragic accident at a cathedral on her wedding day. However, instead of passing on, Lilly finds herself trapped in "The Gray"—a digital and ethereal purgatory that exists between the world of the living and the Great Afterlife.Lilly discovers that her fiancé, Allen, and her former firm are moving forward with her final masterpiece: a revolutionary glass greenhouse in Miami. However, the blueprints are flawed. From the Gray, Lilly realizes that if the building is constructed as designed, it will eventually collapse, potentially killing Allen.