What is the most romantic plot in movies or books? Movies I’d have to give to Casablanca. Books however I’d award to Lydia Bailey by Kenneth Roberts author Northwest Passage. A reserved new Englander in the early 19th century falls desperately in love with a portrait of a young woman murdered in the slave insurrection in Haiti. Then he finds that she’s not only still alive but in mortal danger on that blood soaked island. What happens next is an epic adventure – a tale of love and duty. Interestingly Casablanca was also a tale of duty. Hmmm?