She mistakes the present-day Nobunaga for the historical Oda Nobunaga, and tries to get him to get her pregnant.
One day, Kichō, the 14-year-old wife of the real-life Warring States period warlord Oda Nobunaga, does appear in front of him after having apparently traveled through time.
Because he is a descendant of the historical Oda Nobunaga with a similar-sounding name (written with different kanji characters), his students call him “Mr. Nobunaga.”
She should have been betrothed to Oda Nobunaga in a political marriage, but she time-traveled to the present day.