Rainsford is a hunter and he was with his friend Whitney (another hunter) on a ship. Rainsford fell off the ship after hearing a gunshot. The ship left without him and he swam to shore. Where he saw a jungle and he started walking.
He wandered into the jungle after hearing gunshots. He saw blood and a gun so he tried to find help. He saw a huge castle and he knocked on the door and a gigantic guy named Ivan opened the door with a gun. He explained his situation and Zaroff came to the door.
Zaroff invited him in because he knew his through his hunting books. He explained to him that he hunts but more exotically. He hunts humans, he invited Rainsford to hunt with him the next day and he declined. So he said he was going to hunt him.
Rainsford got some items and then he was on his way to try to live being hunted. He hid in a tree and Zaroff found him, smiled and walked away. He walked and eventually built a trap but it only hurt Zaroffs shoulder.
Rainsford built another trap but this time it killed Ivan. Zaroff went back to his home and Rainsford swam instead of walking through the jungle, he then killed Zaroff after hiding in his curtains.
He had never slept in a better bed in his life after killing Ivan and Zaroff.