It's summer, and the school swimming pool is open for use. While Fuyuki has been dreading this all year (he can't swim), Keroro hatches a new scheme to infiltrate the swimming pool and have some fun on his own, resulting in a confrontation with Natsumi in the pool, where Keroro's amphibious advantage over her is exploited to the fullest.
After the historic Earth versus Keron Swimming Meet, a second interplanetary competition begins at nighttime, as humans and Keronians duel each other with the scariest ghost stories they can think of. While Fuyuki's little-known talent for ghost stories wins the day, the only real loser here is Giroro, who gets jerry-rigged to a meter and subjected to all the scares (and some physical violence) from both sides.
Natsumi echa una carrera acuática contra Keroro y al final, acaba ganando este último
在Keroro軍曹的秘密調查下，他發現學校泳衣的存在。為了調查它驚人的性能，Keroro軍曹等人潛入了夏美學校的游泳池，但是…
Keroro軍曹等人看了電視的鬼故事，決定進行一場地球人與外星人的鬼故事對決。於是大家發表自己最得意的鬼故事，就此展開鬼故事大賽…
