Since I don't know the story, I can't say for sure. But usually, in such stories, the most interesting part could be the moment when the true identity of the unknown visitor is revealed.
The visitor could be an old friend from far away. They might have decided to make a special trip during Christmas to reconnect with their childhood buddies or family friends.
" Guests on the Iceberg " was a the mainland of China film released in 1963. It was directed by Zhao Xinshui and starred Liang Yin, Gu Yuying, and En Hesen. The film told the story of the frontier soldiers and Platoon Leader Yang fighting against the fake Gulandam, and the story of the final victory of Amir and the real Gulandam being reunited. The movie was a suspense war film that was released in the mainland of China on February 2, 1963. For details such as the plot and movie evaluation, you need to watch the movie or look up other information.
The visitor might be strange because of their appearance. They could have an unusual style of dress or a physical feature that stands out. For example, they might be very tall or have a strange mark on their face.
Wu Zhu had appeared in both the television series " Celebrating the Years " and the novel " The Visitor." The chapter that Wu Zhu appeared in was the last chapter.
I don't know the exact main characters since I haven't read it. But it could have a protagonist who is the visitor, and there might be other characters like the locals who interact with the visitor.