After a period of peace, Itsuka Shidou's tranquil days were disrupted by the appearance of a mysterious sphere emitting a spiritual wave, along with a girl of unknown intent. Despite his previous role in saving the Spirits from the throes of battle, Shidou found himself tasked once again with a high-pressure mission: to date and win the love of all the Spirits. With humanity's fate hanging in the balance, the war(date) continues.