The second epsiode of HARUHI-ON!
Yui doesn't come to school the day after Haruhi rejected the light music club. It is then revealed Yui has come down with a fever and won't come to school for a while. Mio, Tsumugi, Ritsu and Azusa panic, as their lead vocalist is missing. They beg Haruhi to join, but Mikuru and Yuki volunteer to join, also. They decide to hold a contest to see who will be Yui's replacement, which Haruhi wins against her will. So from then on, Haruhi was going to be a member of the light music club while Yui was recovering.