In the chaos of 2004, young Fuyuki Hinata envisions a world invaded by frog-like aliens and their UFOs. This dream becomes reality when Sergeant Keroro, on a mission to prepare for the Keronian invasion of Earth, lands in Fuyuki's house. With plans to fix his vital invasion tool, the Kero Ball, Keroro faces a setback when his team is abandoned by headquarters. Stranded with the Hinata family—Fuyuki, his fiery sister Natsumi, and their stunning mother Aki—Keroro and his squad adapt to life on Earth. Despite their grand schemes for domination being foiled by everyday surprises, the aliens forge unexpected bonds with their human companions, discovering the true value of friendship and cooperation.