Honzuki no Gekokujou: Shisho ni Naru Tame ni wa Shudan wo Erandeiraremasen Dai 4-bu - Kizokuin no Toshokan wo Sukuitai!

As Rozemyne wakes up after almost two years she finds out that the world around her has undergone great change causing her to feel like Tarou Urashima from the Japanese fairy tale. However, there is no time for her to get acclimate to the new world as she is quickly sent off to the Royal Academy to become a true noble.

She is presented with the difficult task of raising Ehrenfest's ranking while being surrounded by eccentric teachers and children from other duchies however she is motivated by the Royal Academy's giant library. While there are no other Archduke candidates or members of royalty around Rozemyne commandeers the library!

(Source: TO Books, translated)