She refused to commit suicide because of her Catholic faith, breaking the code of conduct imposed on women of the samurai class and causing a family retainer to kill her instead.

In the Sixth Month of 1582, her father Akechi Mitsuhide betrayed and killed his lord, Oda Nobunaga, making the teenage Tama a traitor's daughter.

Not wishing to divorce her, Tadaoki sent her to the hamlet of Midono in the mountains of the Tango Peninsula (now in Kyoto Prefecture), where she remained hidden until 1584, until Toyotomi Hideyoshi requested that Tadaoki bring Tama to the Hosokawa mansion in Osaka, where she remained in confinement.Tama's maid, Kiyohara Kayo, baptized Maria, was from a Catholic family, and her husband repeated to her conversations with his Christian friend Takayama Ukon.

In the spring of 1587 Tama managed to secretly visit the Osaka church; a few months later, when she heard that Toyotomi Hideyoshi had issued a proclamation against Christianity, she was determined to be baptized immediately.

The death of Hideyoshi in 1598 left a power vacuum with two rival factions forming: Tokugawa Ieyasu in the east and Ishida Mitsunari in the west.

When Ieyasu went to the east in 1600 leading a large army, including Tadaoki, his rival Ishida took over the impregnable castle in Osaka, the city where the families of many of Hideyoshi's generals resided.

The original Jesuit account written shortly after her death instead states Tadaoki had commanded the servants of his household to kill Gracia if her honor were ever in danger.

Ayako Miura's novel Hosokawa Garasha Fujin (English title: Lady Gracia: a Samurai Wife's Love, Strife and Faith) follows history fairly closely.