|Volume 2, Chapter 10|
|Volume||K-ON! Volume 2|
|Previous Chapter||Volume 2, Chapter 9|
|Next Chapter||Volume 2, Chapter 11|
|Anime Adaption||Light Music!|
Despite Yui's promises that she will be fine, it is hard for Ui to leave her side. At school, Ui's friend Azusa asks about Yui's condition and gets really worried about the outcome of the school festival, where she will perform a concert with the other members of her band Ho-Kago Tea Time, after she heard that Yui is still sick. Ui laments that she can't help her sister at all and while she imagines taking the cold from her, they are startled by the Light Music Club's president Ritsu, who came to visit them alongside Mio.
As Mio states that they have to practice without Yui, Ui promises that she will find a way to cure Yui. At the end of the next school day, Ritsu laments the fact that Yui is still missing while drinking Tsumugi's tea. At that moment, a healthy Yui enters the room, surprising everyone inside. To the question where her cold went, she starts coughing which appears fake to the others. Nevertheless, everybody is relieved to see her healthy, so they start practicing. After finishing one song, Mio, Ritsu and Mugi nervously propose to start from the beginning again. After a second attempt, the three are shocked to notice that Yui's play is way too perfect compared to what she could do before. Azusa is the only one who is excited about it and together with Yui, she can calm the others down.
Just as everybody is convinced, Azusa suddenly notices that Yui is calling her "Azusa-chan" instead of "Azu-nyan". After she asked her about it, their teacher Sawako Yamanaka, who was there the whole time without them noticing, surprises the club by stating that Yui is actually Ui in disguise. The cover is ultimately blown by Azusa who asks about her nickname which Yui doesn't know, proving that she really is Ui. After changing back to her usual look, Ui apologizes for the act and states that her sister is still sick and that she simply wanted to do something in the club's favor. Mio states that Ui totally looked like Yui, leading Ritsu to ask Sawako about how she could notice the difference. Sawako tells them that Ui's chest is by far bigger than Yui's which greatly embarrasses her. Azusa then asks Ui about her being able to play guitar to which Ui replies that she managed to come only that far by practicing the last few days which greatly astounds the others.
Ritsu proposes to let Yui rest a bit longer, but her mischievous thoughts are interrupted by Mio. In the meantime, Yui is seen being still as sick as before.