Passage Summary: A historian says people need to know history to help their country, but unfortunately, most people's understanding of history is messed up because they only learn it through entertaining stories about heroes and villains.

Conclusion: The historical knowledge possessed by the general public is inevitably distorted.

Reasoning: Most people learn history through popular narratives that focus on a few famous heroes and villains to maintain interest.

Analysis: The argument relies on a missing link between the 'hero/villain' narrative style and 'inevitable distortion.' The historian assumes that any history focused on individuals rather than broader forces is necessarily inaccurate. To find the necessary assumption, ask yourself: 'What if a story about a hero could still be a perfectly accurate representation of history?' If that were possible, the conclusion would fall apart, so the argument must assume it isn't.