Kero Kero Keroppi no Kero Kero House no Himitsu
Keroppi and Friends: The Frog's Secret House
Keroppi in the Frog's Secret House
けろけろけろっぴのけろけろハウスのひみつ
On a rainy day Keroppi and friends find their elders' old secret club house. But the house ends up being more magical than they thought.