Mind Stone is an adventurous educational game. The game takes place on the planet named Arekaam. Local people gather their knowledge in crystals they call Mind Stones. However the planet gets attacked by aliens known as Knowledge Thieves who are trying to steal the crystals. Player's task is to visit different places of the planet and defeat aliens before they take the Mind Stones. The game consists of a virtual environment and selection of questions from various subjects. Game targeted at primary school students aged 9-14 in Estonia and the project is funded by ÕpiVeski project of University of Tartu.