In a medieval-esque setting, players start as a mercenary and end up teaching at the officer's academy, a school with three houses (hence the name). As a professor, players mentor students from all houses, and then venture out into the world together to put their skills to the test on a grand scale. The houses are the Black Eagles, Blue Lions and Golden Deer, and each one represents a different kingdom in this fantastical universe.
Nintendo announced Three Houses during E3 2018, but aside from an initial trailer, the company has kept details light. The most recent installments in the series -- Fire Emblem Awakening, Fates (Birthright and Conquest) and Echoes: Shadows of Valentia -- came out on 3DS. Three Houses, meanwhile, was built specifically for the Switch.