Episode 314
Keroro takes inspiration from "The Emperor's New Clothes" to create a gun that is invisible to idiots! Later, Natsumi and Saburo are the only members of the school's new Invasion Club, but why are Keroro and the platoon hunting them down during lunch period? Source: crunchyroll
Aired 15/05/2010EP 314 - Episode 314
Sgt. Frog
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.
(Source: Anime News Network)