Tearmoon Empire: Volume 3

Half a year has passed since the Remno revolution ended. Spring has rolled around again, bringing with it one of Mia's favorite occasions—spring break. Freed from the duties of school and station, she’s ready to seize the day! By which she means, of course, do absolutely nothing productive and lounge around in bed all day. Her indolent plans are cut short when her granddaughter, Bel, is whisked backwards through time and deposited in front of her. Just when she thought she was finally done with worrying about the guillotine, she learns of the grisly future awaiting her, in which a war of succession rends the empire in two. Mia herself has been killed by poison, and Bel narrowly avoided execution by leaping through time. Altering the course of history will, of all things, require her to defeat Rafina in the upcoming election for student council president! Underprepared, polling abysmally, and trailed by a granddaughter who inherited all her, erm, Mia-est quirks, she once again finds herself at a historical turning point... without the faintest clue of what she's supposed to do!

[From J-Novel Club]