The third season of the PuniRunes anime begins in the soft and squishy world where the PuniRunes live. These mysterious creatures love nothing more than being gently squished and spend their days happily. Their peaceful routine is interrupted when a new puni-friend appears before them. This is Jewelun, a sparkling creature with a precious gem, who asks the main character Airune for a favor: Come with me.

Jewelun leads Airune to a strange and mysterious place called Kachi Kochi Land, a world where everything is stiff and hard, the complete opposite of their own home. Upon arriving, both Jewelun and Airune undergo a startling transformation as their bodies become hard and rigid as well. To find a way back and uncover the secrets of this new land, they embark on a grand adventure to search for the 12 Shards of Punistar, a legendary treasure said to be hidden somewhere within Kachi Kochi Land.

The main cast includes Megumi Han as Airune, with Fuka Izumi joining as the new character Jewelun. Returning characters include Mikako Komatsu as Enerune, Aya Uchida as Raburune, Tomohiro Yamaguchi as Ururune, Hina Kino as Kuurune, Yuna Taniguchi as the human girl Yuka, and Daisuke Ono as the Narrator. The series consists of 26 episodes and maintains the franchise's tradition of short, approximately 11-12 minute stories that blend daily life with fantastic elements.

Notable narrative arcs within the season include the overarching quest for the Punistar fragments in the rigid landscape of Kachi Kochi Land, which provides a strong contrast to the usual soft and squishy settings. The season also features specific comedic and fantastical episodes, such as a "Freaky Friday" Flip in episode 10 where Yuka and Airune swap bodies, courtesy of another character named Angelrun. The series continues to balance slice-of-life comedy with these more adventurous, conflict-driven storylines as the PuniRunes explore a world where everything is uncharacteristically hard.