A high school student named Kaname Sudou receives an invitation from a classmate to play Darwin's Game - a mobile game unfamiliar to him. Upon launching the app, a green snake bites him, causing him to faint. When he regains consciousness in the infirmary, Kaname is advised by the school to take the rest of the day off, oblivious to the snake bite. Assuming it was just a hallucination, he heads for the train station. Out of curiosity, Kaname opens the app once again and realizes that it's actually a battle game. In his first match, he's shocked when his opponent emerges with a knife, making him realize that Darwin's Game is not a typical game but a fight for survival. Scared and on the run, Kaname must find a way to survive.