It is summertime for the girls; that means one thing: comfortable summer uniforms! Tsukasa and Kagami are fraternal twins, but Konata shows them the similar and different characteristics they share. Konata, Kagami, and Tsukasa each try to put their hair into a ponytail, just to see who looks best. Unfortunately, Kagami is the only one who cannot pull it off.

The group, plus Cousin Yui and Nanako, go to the beach for some summer fun. After Yui races down the road, and Nanako gets really lost, they finally make it and spend a night in a Japanese inn. After a day at the beach, and Nanako becoming too drunk to drive, they go back to the inn for a shower and to spend another night. After arriving home, the twins have to clean their bedrooms, Konata discusses cleaning tactics with Kagami, and Miyuki is told she has to go see the dentist, or her mom is bringing the dentist to their house.

It is time for tests! Unfortunately, Konata cannot seem to concentrate on studying and instead reverts to slacking off and playing games. She tries to ask Miyuki about good study habits, but in the end she does bad on her tests. Tsukasa got help from her sister and this time got better scores, but Kagami's scores were still higher despite her own scores going down somewhat. Later, Konata and the Hiiragi twins go to a cake café but end up taking too much and must finish it all or pay an extra price.

Konata persuades Kagami and Tsukasa to come along with her to a festival of sorts: a convention called ComiKet. There, Konata tells the twins to follow her plan of buying new manga, Kagami learns how intense some manga can be, and Tsukasa gets swept into the crowds and ends up lost.

Later that day, the girls go to another festival, with this one celebrating New Year. The girls discuss why Kagami is in a different class than everyone else, Konata draws a bad fortune, and the origin of Kagami's name is revealed.

Konata pesters her father for money, and apparently he likes when she does that. Konata wishes her online friends a happy new year, including her teacher Kuroi. Konata starts to believe that the reason why her teacher doesn't have a boyfriend is because she's always online playing games.

On Lucky Channel, it was previously announced that Akira would appear in the actual show starting with this episode, but she was unable to because she got sick.

The girls go to a concert entitled "The Jam of Haruhi Suzumiya".

Kagami explains how much her pet goldfish has grown.

Konata actually finishes her homework, Ms. Kuroi accidentally erases a saved file in one of Konata's games, Miyuki talks smack about Ms. Kuroi, and Konata's dad is thinking about remarrying... or not! April Fool's!

The girls enter their third year of high school, and they see who's in what class for this year. Once again, Konata, Tsukasa, and Miyuki are in the same class, but Kagami is in a different one from them. Meanwhile, Konata's cousin Yutaka and her new friend Minami Iwasaki enter their first year of high school.

On Lucky Channel, it's announced that Akira will have a live concert next week.

Konata thinks about what animal each of the girls, including herself, would be. She sees herself as a fox, Tsukasa as a dog, Yutaka as a squirrel, and Kagami as a bunny.

Konata and Miyuki discuss things that can improve one's eyesight.

Konata complains about how the recent elections have been screwing up the TV schedule.

Tsukasa tries reading newspapers, but it's not long until she finds them hard to read.

Yutaka and Iwasaki's class plays dodgeball during P.E. Later, they hang out with two of their classmates, Hiyori Tamura and Patricia Martin.

On Lucky Channel, Akira and Shiraishi introduce the newest characters of the Lucky Star cast. However, Akira is mad at the fact that she still hasn't appeared in the actual show yet.

Konata and the girls discuss parents who check through their children's e-mails and text messages, how much money Konata spent at Comiket, and how hot it is even though it's September.

Yui meet's Yutaka's friend Minami for the first time, and Minami gets even less insecure about her... growth.

Tsukasa tries different methods to wake up early in the morning. All of them failed.

Hiyori thinks of some good ideas for her manga, but when she tries to write them down, she just can't seem to remember them.

Konata's class embark on a school excursion to Kyoto and Nara. During the trip, Kagami receives a letter from a boy asking for her to meet him at night. What could this boy possibly want from Kagami?

On Lucky Channel, Shiraishi returns from his journey from Mount Fuji and gives Akira the famed Mount Fuji water she wanted. When Akira is disgusted by the taste of the water, Shiraishi finally snaps!

Konata and Yutaka catch a cold, and Yutaka's friends, Minami, Hiyori, and Patricia, come and visit her. They, Konata, and Yutaka discuss younger-sister-moe, Minami's lack of breasts and how Hiyori doesn't want Yutaka to read her doujin manga.

After seeing a TV program about how xylitol chewing gum can eliminate cavities, Miyuki decides to test this out. As a result, one of her fillings comes out and she has to go to the dentist.

Kagami and Misao play a video game together. Although Misao is terrible at playing them, she seems to be having more fun than Kagami who's playing to win.

Patricia tells Kagami what music she's been listening to lately and how much she would like to have a maid.

Miyuki tells her mother about her friends' opinions on Minami, but they seem to contradict with what Miyuki's mom recalls from Minami's previous actions.