Krabi Yay Yut Chak is a free action game based on the original novel by Kim Yong. In the game, you play as the protagonist, a man named Krabi, who is hired to investigate the murder of a family that was killed by a group of mysterious assassins. In the course of the investigation, you will encounter many mysteries that you will need to solve in order to find out who is responsible for the murders.

As the game progresses, you will find out that the family was not killed by a lone assassin, but by a group of several assassins. You will also find out that the reason for the murders is much more mysterious than you first thought.