In the continent of Landia,Kazuya Souma the new king of  the United Kingdom of Friedonia.
Along the way there are the Union Trinity such as The Kingdom of Nohr ruled by King Xander, The Kingdom of Hoshido ruled by King Ryoma and The Kingdom of Valla ruled by Queen Corrin.  Kazuya Souma has decided to form a relations with the Union Trinity.

Kazuya x Corrin x Liscia x Harem