Sergeant Keroro serves as the Captain of the Space Invasion Forces Special Advance Team from the 58th Planet of the Gamma Storm Cloud System. He was sent to the planet Pokopen (also known as Earth) to gather intelligence for his planet's invasion force. He is also a frog. After his ship crash-lands on Earth, he takes shelter in the Hinata household, but the two children, Fuyuki and Natsume, find him and confiscate his alien weapons. When his people discover that the Pokopenians are aware of his presence, Keroro is abandoned—left to fend for himself in this hostile world. However, he is not alone; four other pre-invasion agents are also lurking on Earth.