Wakasama Goranshin!

Two childhood friends, one from a former noble family, attend a school located on the grounds of a former castle. One night, one of them falls from the school's roof and is hospitalized. When he recovers, the other friend is shocked to find that his personality has changed dramatically, speaking in an archaic style reminiscent of old Japan. Meanwhile, a young man works as a secretary for a CEO who is given a mysterious elixir by a visiting acquaintance. After drinking it, the CEO transforms into a child, and the secretary also experiences unexpected effects after some of the liquid touches his lips.