Summer vacation has just begun. Konata, the Hiiragi twins and Miyuki go to a summer festival clothed in yukata. Yui Nanami is first introduced in this episode, currently on patrol at the festival. Konata and Nanako chat over an online game. Later on, Konata and the twins meet and do homework together. Back at her house, Konata finds a rare drop and celebrates it with her online friends.

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.