Romilly Shepard finds comfort in the hard facts of science. She lives with her friend Martha, also an atheist, and they see each other as rationalists who stand elbow-to-elbow against an irrational world.
Intent on debunking, Romilly and Martha sign up for a comparative religion class, but the instructor, a graduate student and preacher named Ernest, challenges Romilly's assumptions. His open-mindedness and tolerance broaden Romilly's mind and win her heart.
Martha feels betrayed by Romilly's love for a preacher, and Ernest’s congregation thinks Romilly is a heathen in need of salvation. Romilly fears she’s nothing more than Ernest's Convert-an-Atheist Project.
But when a chronic disease threatens Ernest's life, Romilly must take a crash course in faith and hope.