Watch Date A Live: Date to Date Online

Bundled with the 9th volume of the original novel, it is the unaired 13th episode of the TV series.

Shidou Itsuka faces greater peril than ever due to his continued involvement with Ratatoskr. He has already sealed 10 Spirits, and Isaac Westcott, leader of Deus Ex Machina Industries, has finally decided to kill Shidou and plunder the Spirits' powers for himself. To achieve his goal, Isaac declares an all-out war against Ratatoskr, forcing the organization to exhaust its resources to ensure Shidou's survival. Despite being severely outnumbered and outmatched, a glimmer of hope exists in the form of the Spirit of Time, Kurumi Tokisaki. Shidou must seal and acquire Kurumi's power to travel to the past and confront the Spirit of Origin—the catalyst that started it all.

War(Date), resumes.The peaceful days of Itsuka Shidou returned without having to save the Spirits from the relentless battle days. But, the peaceful days were interrupted by the emergence of a mysterious sphere emitting spiritual wave――as well as a mysterious girl who showed herself at the same time. What is her purpose of keeping an eye on Shidou……? The mission that had been entrusted to Shidou under the tense situation was, “Date all of the Spirits, and make them fall in love?!”――With the fate of humanity at stake, the war(date) resumes!(Source: Date A Live Wiki)

Fourth season of Date A Live. The story begins in the world of Eurasia, where a phenomenon known as a “spatial quake” causes the death of about 150 million people. 30 years after this tragedy, we follow our protagonist Shido Itsuka and the world is still suffering from these quakes, albeit they are much smaller. One day, Shido comes across a mysterious girl at ground zero of a spatial quake. From his adoptive sister, he learns the girl is one of the “Spirits.” Beings from different dimensions that cause these quakes. So Shido is tasked to seal these beings’ powers to save the world. But to do so, he must woo and kiss these girls. And thus begins the journey of our protagonist as he continues to increase his harem of superpowered girls who all try to take Shido for themselves.

Shidou Itsuka carries on with his quest for Ratatoskr in finding Spirits and trying to seal their powers, all while maintaining his relationships with the ones he had already sealed. Moreover, as new Spirits appear, he must undergo more complicated trials—all to put a stop to further disasters as he discovers more about the Spirits' origin. [Written by MAL Rewrite]