Episode 324
Natsumi finds herself plagued with a plethora of "Do Not Push" buttons. How long can she hold out before pushing one of them? Later, the Keroro Platoon enters the Kero Ball in order to rescue Natsumi and Fuyuki from a mind-boggling invader level check quiz. Source: crunchyroll
Aired 24/07/2010EP 324 - Episode 324
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)