In the final episode of the season, Ganta and Isaki embark on an adventurous journey to the Mawaki Site, an ancient and well-preserved archaeological site on the Noto Peninsula in Japan.

At the beginning of the episode, we see Ganta convincing Isaki to go on this trip with him, even using the line, "Please let me kidnap you." Isaki, who struggles with overprotective parents, is caught off guard by Ganta's bold invitation and eagerly agrees.

Ganta and Isaki then set off for the Mawaki Site, known as one of Japan's best-preserved Jomon sites, with a history dating back approximately 6,000 years. The site, rich in pottery and artifacts, was continuously inhabited for 4,000 years and features unique characteristics from the Jomon period.

The atmosphere and sense of adventure surrounding them heighten their emotions as they explore the site. Overwhelmed, Ganta confesses his feelings to Isaki. Although Isaki doesn't explicitly reciprocate, she expresses that this moment is the happiest of her life. They decide to capture their feelings and experiences in photos. In a particularly memorable moment, Isaki suggests taking a distinctive photo to commemorate their adventure.

Meanwhile, Isaki's parents, having learned of her whereabouts, drive to the Mawaki Site to bring her home. They arrive before the first bus and pick her up, seemingly displeased with her for undertaking the trip.

Later in the episode, it is revealed that one of the photos Ganta took at the site wins a national photography contest. This victory boosts the Astronomy Club's reputation at school, which was one of the main goals of their club trip.

By the end of the episode, the narrative hints at the continuity of Ganta and Isaki's relationship, with a sense of closure for this special chapter of their story. They return to their daily lives but with a shared experience that seems to have changed them both.