Seniors!
Yui and the other girls start their third year at high school (Azusa's second). Yui, Mio, Ritsu and Tsumugi are surprised that they, along with Nodoka, have been put into the same class. It soon becomes apparent that their new homeroom teacher, none other than Sawako, had arranged it that way so she had fewer names to remember. With Azusa being the only second year of the light music club, the gang become determined to get new members so that she will not be the sole member when they graduate. However, their various attempts to attract new students fail, so they focus instead on their performance for the freshman reception. Azusa becomes depressed that no new members show up afterward, but after talking with Ui and Jun and overhearing Yui's comments, she decides it is fine with just the five of them for now.
Aired 07/04/2010EP 1 - Seniors!
K-ON! Season 2
It is the new year, which means that the senior members of the Light Music Club are now third-years, with Azusa Nakano being the only second-year. The seniors soon realize that Azusa will be the only member left once they graduate and decide to recruit new members. Despite trying many methods of attracting underclassmen—handing out fliers, bringing people into the clubroom, and performing at the welcoming ceremony—there are no signs of anyone that plans to join.
While heading to the clubroom, Azusa overhears Yui Hirasawa say that the club is fine with only five people and that they can do many fun things together. Changing her mind, she decides that they do not need to recruit any members for the time being.
K-On!! revolves around the members of the Light Music Club as they experience their daily high school life. From rehearsing for concerts to just messing around, they are ready to make their last year together an exciting one!
(Source: MAL Rewrite)