There's an old man who's very accurate at fortune-telling. We haven't seen him before, but he told us about his previous experience. What's going on?

Answer 1

This plot can be developed into a mystery novel. Here are some possible plots:

The old man might have obtained his previous experiences through some means, such as dreams, memories, or soul out-of-body experiences. This way, the old man could accurately predict what had happened before without meeting him.

The old man might have used some kind of magic or supernatural ability to sense the inner world or past experiences of others. This ability might require some special training or faith to master.

The old man might be a prophet. His job was to predict the future. He could collect information about people, including past experiences, interpersonal relationships, health conditions, and so on, and then make predictions.

In any case, the old man's prediction ability was very powerful, and it might surprise and confuse the protagonist. In the subsequent development of the story, the protagonist may need to delve into the old man's ability or face the future events predicted by the old man to understand the true meaning of the old man's prediction.