Even the actors who play the characters in the work wish to celebrate the tenth anniversary of the manga's debut for Yuru Yuri: The Amusement Club's four middle school girls, Akari, Kyouko, Yui, and Chinatsu, want to go back in time. But because of their imaginative leaps, they miss the mark and speculate on how the club might have operated in the Paleolithic era. It isn't until their classmates Ayano and Chitose show up that things start to run well. Although it should be a routine celebration, preparations must obviously be made first, and even preparing cookies follows an odd pattern.
