The 'lucky ones' in 'We Were the Lucky Ones - A True Story' are probably the characters who managed to escape some sort of tragedy or misfortune. It could be that they survived a war, or perhaps they were able to overcome poverty or illness. Maybe they were a family that stayed together through tough times when many others were torn apart. It all depends on the context of the true story.
Maybe they had the right resources at the right time. For example, if it was a survival story, they might have had enough food and water when others didn't.
The main theme could be about survival. In many stories, characters face challenges and have to find ways to endure, and perhaps this novel is no different.
The 'we' in the title likely refers to the group of people whose story is being told. It could be a family, a community, or a group of individuals who had a shared experience.
Probably the main theme is about counting one's blessings. Since they consider themselves the lucky ones, it's likely about finding the good in difficult situations.
The main theme is often about survival and family. It shows how the characters endure difficult times and hold on to their family bonds throughout hardships.