In Peru's mountaintop city of Machu Picchu, Fuyuki Hinata and the Keroro Platoon explore a deserted temple at the start of the movie. During their exploration, Keroro unintentionally triggers a trap that reveals a concealed chamber with a large blue crystal at its center, mounted on a stand containing a key. By mistakenly leaning on the key, Keroro activates a mysterious machine that causes the temple to tremble. The team makes a quick exit as Keroro loses his Kero Ball, and Fuyuki spots a fleeting glimpse of a radiant young lady before they depart. While the girl sprouts glowing wings and watches their retreat, something inside the crystal begins to grow ominously.