The Guardian of the Atobe Family

Nana, a person from a thousand years in the future, accidentally fell into a time tunnel and arrived in Japan's Edo period. By a twist of fate, she became the guardian of the Atobe family. Hundreds of years later, young Keigo Atobe accidentally discovered Nana asleep in a crystal coffin in a secret room of the old residence. When Nana wakes again, and Keigo gradually grows up, their story begins...