Hearts of Iron IV is a grand strategy war game set during World War II, where players command a nation and guide it through diplomacy, warfare, industry, and political decisions. You manage armies, research technologies, produce equipment, and shape global alliances while responding to historical or alternate scenarios. The game features deep strategic systems, detailed military planning, and extensive mod support on PC. With multiple playable nations, complex mechanics, and rich historical depth, Hearts of Iron IV rewards long-term planning and strategic mastery.