Stop the Old Fox (2016)

After the sudden death of her adoptive father Shimada Mataemon, Nui, whose own father met an untimely death when he was about to expose the corruption of the shogunate becomes determined to expose the collusion between Kannouji, and the unforgivable relationships between the ladies in waiting of the inner palace and the monks. Nui is undertaking this undercover investigation without regard for the danger she is putting herself in, for the sake of Shinnosuke whom she secretly loves

Unfortunately the movie Stop the Old Fox is not yet available on HBO Max.