In the far future, humans no longer needed war. So when an alien threat approaches Earth, a test must be created for the prospective commanders... A timegate has been created into 4 past periods, where you must test your strategic skills, and when you pass all four tests, take your forces against the alien threat... The four periods are 2025, WW2, Roman Empire, and prehistoric. The turn-based movements are hex-based. You move the unit stacks. When two opposing stacks meet, you drop into tactical combat mode, where the individual units in the stack manuever on the smaller tactical map.