Yo-Jin-Bo ~ The Bodyguards

Sayori, a more-or-less ordinary high school student, is spending her summer assisting at an archaeological excavation when one day she notices something shining half-buried in the mud. As she looks more closely and picks it up the treasure, her adventure begins. That night in her dreams a girl, princess of the ancient Mochizuki clan, begs her for help in preventing her assassination. The next morning, Sayori wakes up in – Hatsuhime castle?!? In what seems like the impossible, she must now use her wits to change history.