Set in 1987, Carla's Song tells the story of love in a time of war. The plot follows the relationship between a Scottish bus driver, George Lennox (Robert Carlyle) and Carla (Oyanka Cabezas), a Nicaraguan refugee living in Glasgow. George first encounters Carla when she sneaks onto his bus without paying the fare. They go out for coffee but Carla seems hesitant to tell George anything about her life or where she's from. When Carla needs a place to stay George arranges for her to stay at his friend's place.