Rainsford faces two major "unknowns" in "The Most Dangerous Game." The first is the island itself; he is intrigued by the description of "Ship-Trap Island" and, while he does not fall overboard on purpose, is thrown off balance by the sound of gunshots from out in the dark night. By swimming to the island and pulling himself ashore, Rainsford moves towards discovering the secret of the island.
The second major unknown is General Zaroff. Rainsford is astonished to find an enormous chateau on a seemingly deserted island, and equally astonished to discover a civilized man living in secret. Their conversation reveals secrets: Zaroff uses the island's topography to wreck ships, and then he captures and hunts the men who survive. In this fashion, the two major "unknowns" become "knowns" to both the reader and Rainsford.
Rainsford encounters many unknowns throughout the story The Most Dangerous Game. Before he falls overboard and lands on the island, he is faced with the mystery of the island in the first place. He has heard his shipmate's tales about the place, but when he makes the decision to swim toward the island, he faces the unknown because he really cannot be sure what he will find there.
Once he arrives at Zaroff's mansion, he meets the general and Ivan. He is unsure what to think of both men because they seem so peculiar. Over dinner with Zaroff, Rainsford is intrigued by the discussion about hunting, but again faces the unknown. Although Zaroff seems to have previous knowledge about Rainsford, Rainsford knows very little about Zaroff.
After Rainsford discovers that Zaroff's latest hunting craze is to track and kill human beings, Rainsford does not know how he should handle the information. And when Rainsford realizes he will be the subject of Zaroff's next hunt, he has many fears about what will happen to him.
Once released onto the island to be hunted, Rainsford experiences the unknown yet again. He is not familiar with the island like Zaroff is, so he faces a significant disadvantage. He really doesn't know how good a hunter Zaroff really is, so at first, he underestimates his foe.
Once Rainsford finally outsmarts Zaroff, sneaks back into the mansion, and kills the hunter, it is implied that it is unknown what Rainsford will do next.