Keroro, a frog-like alien platoon captain, is sent to scout Earth, codenamed Pokopen by his species, ahead of a full invasion, but he crash-lands and loses his equipment when Fuyuki and Natsumi Hinata discover him hiding in their house. Rather than report the security breach, his superiors leave him stranded, so Keroro settles into the Hinata household while four other advance-team agents scattered across the planet slowly resurface. Each chapter follows his halfhearted invasion schemes, which usually collapse into chores, hobbies, and Japanese seasonal events instead.