|Japanese air date||April 24, 2009|
K-ON! episode #4
Mio finds a box filled with stuff from the previous Light Music Club, including a cassette tape of the previous club's performance at the school festival while taking pictures with her camera. Energetically, she decides to hold a training camp to finally upgrade the band's skills since she does not want to feel inferior to their predecessors. Ritsu and Yui ecstatically plan to have lots of fun while Tsumugi thinks about it as a good chance to strengthen their friendship. Tsumugi offers a villa owned by her family as the location.
Yui oversleeps at the day of their departure and hardly makes it in time. Shortly before arriving by train, Mio, Ritsu and Yui learn that the villa is located at the sea.
Arrived at the villa, the guests are greatly impressed by the amazing extravagance, much to Tsumugi's indisposition. Mio is almost instantly outnumbered and the four go to the beach to spend the day having fun. In the evening, Mio is completely carried away by them and totally forgot their real purpose, training.
Filled with regret, Mio forces Ritsu and Yui to train, just to see them to be too exhausted for it. To cheer her up, Mugi, Ritsu and Yui plan a surprise for her. Using fireworks, they hold a provisorily concert for her with Yui in the spotlight. Mio then understands what Mugi meant earlier when she told her that her band must not automatically be bad just because the members aren't that experienced. She then shows her friends the tape from the previous club members. At that moment, the tape changed to side B, revealing a scary chant that scares Mio that much that Ritsu's following joke completely wears her down.
Returning to the training room, Yui shows for the first time that she has perfect pitch as she managed to play the tape's song at the first try without a mistake. After practicing some more, the four take a bath at the villa's open-air bath where Yui thanks Mio for inducting her into music.
In the last scene, Ritsu shows Mio the printed photos from her camera. One picture shows Mio hugging her pillow while sleeping, which leads Mio to knock Ritsu out.