Everyone's favorite bear, Yuna, is living it up with her friends on a seaside getaway in Mileela, but there doesn't seem to be enough time in the world to enjoy all the summer activities! When Yuna learns of a mysterious moving island that suddenly appeared off the coast of Mileela, she's unable to contain her curiosity. After creating a distraction, Yuna makes way for the strange island—and a new adventure. However, the island surpasses even her wildest imagination, containing an abundance of nature and powerful monsters ready to attack. Will Yuna and company make it through their vacation unscathed?