At the 2017 annual eSports world championship, “The International”, an Artificial Intelligence agent was unveiled that could play against some of the world’s best players at DOTA 2, a popular online game considered one of the most complex video games ever. While this demonstration was based on a 1 vs 1 version of what is normally a 5 vs 5 game, and play was limited to a reduced section of the map, it was a major coup. After the demonstration, and to the surprise of both the gaming and artificial intelligence communities; the developers fueled by the excitement of the win announced to the crowd that they will be back the following year with a new AI that can play the full 5 vs 5 game. ARTIFICIAL GAMER follows the journey of the scientists and engineers at OpenAI, as they develop their artificial agent. During their quest, they face the unique challenges of building one of the largest and most complex AI systems in history, in only one year.