King's Game

Nobuaki Kanazawa is a high schooler. One day, he receives an email with an order from someone calling themselves "king". At first, the orders were normal. However, they started to escalate as time passed. Anyone not following the order was to be "punished" with "death"... The "King's Game" with their lives on the line has started!!! What awaits Nobuaki, who's facing against the invisible "king"!? (Source: Coolmic)