In this project, I will challenge myself exploring the AI applications in 3D games by implementing AI NPCs in a hide-and-seek game. With understanding of the navigation mesh, the agents in the game are able to find the path towards the destination and avoid obstacles in the game map. Hiding is the most important part of my AI, so ray casting is widely used throughout my codes to check if the player can see the NPC. Dot products are calculated to find the proper hiding spots on the map. As a result, I finished a simple but complete hide-and-seek game with AI NPCs acting reasonably. Through this project, I saw the potential of how complicated this project can become and accumulated my interests to continue this project later to improve more on real AI behaviours.