For young priest Strobel, a bus trip from Lake Constance to Lourdes turns into an ordeal. Accompanying a group of Catholic pilgrims, he not only has to deal with a recalcitrant bus driver and an overly serious nun. He is horrified to discover that his lover Theresa has stowed away among his flock. She corners him, forcing him to finally reveal their relationship. After all, she is expecting his child. As the bus trip turns into a grueling odyssey, Strobel struggles to keep his double life hidden.