Centennial Romantic Sleeping Princess

The year is Taisho 8 (1919). Yuzuki, a village girl, was about to marry Yuichiro, the heir of the Kaguragi clan, which has ruled their village for generations. But facing a spreading epidemic, Yuzuki and Yuichiro decide to hibernate for a year by taking the poisonous plant called "tokohana," that is supposed to have the "power to stop time." But when Yuzuki wakes up from her long sleep, a shocking new reality awaits her.

(Source: Hakusensha, translated)

Note: The volume includes a bonus chapter and two additional one-shots.