Bettina's end seems near. As she feels her days draw to a close, her mind travels back to her first love, a young French scholar who introduced her to Guillaume de Lorris' 13th-century masterpiece on courtly love, Le Roman de la Rose. In the Roman, a dreamer enters a garden, where Eros is holding court. The dreamer discovers a perfect rosebud, and yearns to pluck it, but is dissuaded by the protestations of the others in the garden. Thereafter, he meditates on the unattainability of earthly love -- to pluck the rose is to destroy it.

Bettina knows all about earthly love. Bettina is a long-distance bus who grew devoted to a young medieval literature scholar on the Paris-Lyon run, when he traveled home from school on her every Friday night. She remembers the night he met the girl, and how he began to tell the girl Le Roman, as only he could. When it became clear that her scholar would not have time to finish his story before the end of the journey, Bettina broke down by the side of the road. The consequences were swift; Bettina was removed from service and never saw her scholar again. She had sacrificed herself so that her scholar could complete the story and be happy with another. Even years later, Bettina's devotion to her scholar remained perfect.

Spencer and Phoebe are star-crossed lovers. They have abandoned their separate lives in Red Deer and Montreal to restore Bettina, who has fallen into disrepair. They start the Bettina Line, crisscrossing the continent with a few select passengers at a time. Bettina carries them lovingly, longingly, grateful for a last chance to make the love between two people into something perfect. But as the miles pass, and things turn more complicated between Phoebe and Spencer, Bettina reflects on the lessons of love she first learned from her scholar. Bettina is an unusual, quirky love story. A romance with wheels.