Despite his tiny, childish size, Heine Wittgenstein is a smart guy who inspires respect, equally charming and serious. Thus, the king of Grannzreich has asked Heine to take on a hard assignment that has drove many others away in the past—become the next royal teacher to four princes in line for the throne. Each of the four heirs has a different and bothersome personality: Licht, the flirting youngest prince; his immature elder brother Leonhard; Bruno, the studious third prince; and Kai, the oldest and most reserved of the four. Heine seeks to connect with each of the princes in order to groom them for the throne, which results in hilarity. However, Heine's enigmatic history and sinister undercurrents in the present may jeopardize the unity within the group.