Based on a popular manga by Hirai Mari, published on Hana to Yume Comics by Hakusensha. The animation was made into a 59 minutes OVA published on a single DVD (or two VHS on December '98 and January '99) by SPE Visual WOrks. This 2-part OVA is one of the story arcs of the manga, namely "Autumn Threat" (Aki Kyogen).
The story takes place on Kamakura period (1192-1333) in Japan. Kagetsu is a member of a feline tribe. Member of feline tribe is capable to become a male or a female depending on "its" mate. However, Kagetsu often refers "itself" as a "he" because he used "boku" to refer to himself.
On one day in autumn, Kagetsu approaches Arimasa Tsuchimikado, a Yin Yang fortune-teller for the emperor, and tell him that he would like to bear his kids (note: people with weak heart for yaoi series should not watch this, you've been warned).
Meanwhile, a "shadow" assasin (a man in black robe with his panther) attacked the shogunate. Arimasa is accused of conspiracy to kill the shogun, therefore both Arimasa and Kagetsu have to escape and run into the mountains.