On the day of the Tanabata festival, Shidou Itsuka happens to meet the eerie Kurumi Tokisaki, who proceeds to ask him out on a date. Although nervous, Shidou accepts the offer. The two spend their time visiting a planetarium, buying food at the festival, and trying out a mock wedding ceremony. Meanwhile, Shidou's friends—Tohka Yatogami, Yoshino, and Kotori Itsuka—are looking for him, while also enjoying the festival themselves.

As Shidou spends the day with Kurumi, he begins to notice an unexpected softer side of her. He knows that Kurumi is infamously called the "Worst Spirit," but the girl standing before him is a gentle soul. However, as the day draws to a close, Shidou finally begins to understand the truth behind it all.

Note: Unaired 11th episode of the TV series bundled with the third volume of Date A Live Encore.