Muteki no Mirai Daisakusen

A new type of marriage called "Seikon," or Holy Marriage, is introduced to address a falling birthrate. Individuals designated as "Saints," who are extremely wealthy, are granted the right to multiple spouses. Eiko Akira, from a financially struggling background and seeking stability, becomes drawn to Iida, a newly named "Saint" at her school who is described as princely. However, she faces competition from others who are also pursuing his attention.