The legend of the Divine Gate is a story told to young children that depicts the merging of the living world, the heavens, and the underworld. "Adapters"—people born with unique elemental abilities gifted to them from the union of these worlds—formed the World Council, an organization which controls the chaos of the Gate by portraying its legend as nothing more than a myth. These Adapters train in a special academy owned by the World Council that allows the students to hone their skills. Aoto, a teenage boy with exceptional water powers and a tragic past, rejects the offer to join the academy numerous times—until he is successfully pressured by the energetic wind user Midori and stubborn fire user Akane. Together, with the World Council and their mysterious leader Arthur, they seek out the Gate in the hopes of uncovering the truth. But in order to reach their goals, they must unite and overcome their own despair while dealing with behind the scene mischief. [Written by MAL Rewrite]

Yuuta Hibiki wakes up in the room of Rikka Takarada and notices two things: he has no memories, and he can hear a mysterious voice calling his name from a nearby room. On further inspection, he finds a robot—which introduces itself as Hyper Agent Gridman—behind the screen of an old computer. Much to Yuuta's surprise, Rikka cannot hear Gridman, nor can she see the ominous monsters looming over a thick fog as it envelopes the town outside. Another giant monster materializes in the city and proceeds to wreak havoc. Amidst the confusion, Yuuta is once again drawn to the old computer and merges with Gridman. Suddenly, he appears in the middle of the battle and is forced to fight the monster. Together with Rikka and fellow classmate Shou Utsumi, Yuuta forms the "Gridman Alliance" to defeat the monsters plaguing the city and find whoever is responsible for their emergence. [Written by MAL Rewrite]

Unaired episodes included in the Blu-ray/DVD releases of Volume 2 and Volume 7.

Continuing their treks through the high peaks of Japan, the mountaineering girls are back for more! First-year high school student Aoi Yukimura, a shy girl with a fear of heights, and her wildly energetic friend Hinata Kuraue set out once again to conquer the perils of backyard camping trips, summer homework, and even a climb on the mountain of their dreams. Joined by middle school student Kokona Aoba and their knowledgeable upperclassman Kaede Saitou, the squad members are ready to take on whatever slopes and challenges they might face, no matter how steep. Through their shared hobby of mountain climbing, they bond closer than ever and even make new friends on trails all over the country. Whether it is just a local hill or the tallest mountain around, nothing is too much for Aoi and the crew to handle. They will climb, stumble, and rise to even greater heights together! [Written by MAL Rewrite]