The event that sparks the main conflict in "The Most Dangerous Game" and sets the rising action in motion is Rainsford's realization that General Zaroff means to hunt HIM that night, and that he has no choice in the matter. If he refuses to fight, then Zaroff will send Ivan out after him. Either way, he will face one of them in a fight to the death.
Rainsford first learned of Zaroff's "hobby" during their conversation the night before. Zaroff is very excited when he learns the identity of his island's newest arrival. He tells Rainsford he has read his books on hunting before, and both men shares their stories and enthusiasm for hunting.
This conversation takes a turn, though, when Zaroff lets it be known that he has grown bored with most forms of hunting. As he explains:
"Hunting had ceased to be what you call `a sporting proposition.' It had become too easy. I always got my quarry. Always. There is no greater bore than perfection.... No animal had a chance with me any more. That is no boast; it is a mathematical certainty. The animal had nothing but his legs and his instinct. Instinct is no match for reason. When I thought of this it was a tragic moment for me, I can tell you."
To combat this problem, Zaroff explains, he "had to invent a new animal to hunt," one with "the attributes of an ideal quarry." These attributes, he continued, include "courage, cunning, and, above all, it must be able to reason."'
When Rainsford objects that no animal can reason, Zaroff insists that there is ONE who can. Rainsford now understands Zaroff's "game," but says this is not hunting, but murder. Rather than feeling chastised, Zaroff is amused by his words:
The general laughed with entire good nature. He regarded Rainsford quizzically. "I refuse to believe that so modern and civilized a young man as you seem to be harbors romantic ideas about the value of human life. Surely your experiences in the war--"
Rainsford does not let him finish his sentence, but rather makes it clear his wartime experiences did not make him "condone cold-blooded murder." Still, Zaroff goes on laughing and says:
"I'll wager you'll forget your notions when you go hunting with me. You've a genuine new thrill in store for you, Mr. Rainsford."
The next day, Rainsford learns they are going hunting together, and he will be the prey. The game is on - and the rising action takes off at a fast pace.