Lady versus Lady - a prequel

M1, T5: Selenia and Tomomi remark on their days since their first meeting at Hakureiryo Academy, where they eventually become rivals to see who's the more diligent and accomplished lady. Meanwhile, the Academy's water system goes out-of-order, and the school has to use an indoor natural hot spring for the time being--and the servants and uppers are getting a little too cozy.