Keroro

This is episode 0, the prequel to the main Keroro Gunsou anime series. KeroZero was shown in theaters with Keroro Gunsou Movie 4. On the day of Keroro battalion's departure from Keron Planet to Planet Earth, an opposing alien species assails the Keron space station, where Giroro and Zeroro (later known as Dororo) are waiting for Keroro to arrive.

Keroro is a frog-like alien sent from his home planet on a mission to conquer Earth. But when his cover is blown, his battalion abandons him and he ends up in the home of the Hinata family. There, he's forced to do household chores and sleep in a dark basement that was once supposedly a prison cell haunted by the ghost of an innocent girl. He even spends his free time assembling Gundam model kits. During his stay, Keroro meets up with subordinates who were also stranded during their failed invasion.

Sergeant Keroro and his four subordinates came from the planet Keron to the Earth to conquer. However, without notice, they began to enjoy the life on the Earth. Keroro was supposed to stay with Hitana to get the chance to conquer the Earth, but he became friend with Hinata's son, Fuyuki. Today, as usual, Keroro goes to buy his favorite Gundam plastic model with Fuyuki. On their way home, they find a small shrine, and enter. There, they find a vase, and happens to break it. Since the next day, strange things happen all over the town and people are in panic. Inside the vase, Kiruru, Keron's ancient ultimate weapon was sealed. At the moment, Mirara who holds the secret of the Kiruru appears and informs them of the only method to save the Earth. However...

The Keroro Platoon, living their lazy days as if invasion were nothing. Then one day, they face a series of bizarre phenomena erupting across the nation. Feeling a sense of crisis, the Keroro Platoon rises up, staking their pride as invaders! What is the meaning of the mysterious symbols they encounter wherever they go. The largest-scale battle in the history of "Sgt.Frog" begins in the Reiwa era! Note: Relations are provisional and will be updated when more info is announced.