It's not a direct sequel. The main plot concerns a tortoiseshell cat divinely transformed into a woman, now named Kagaya-hime, who makes a name for herself as a warrior: she is the protagonist of a story being written by Harueme, an elderly princess on her way to a convent in the last journey of her life. Mostly it's setting and one notable character overlap (you'll spot it when you get there) that connects the two novels. I think you'll like it as well.