Ninja Assassin: A Time Travel Adventure - Erotic Fantasy, #6

Some assassins have a conscience. When Riley's time machine drops her in 16th-century feudal Japan, she finds herself part of a secret ninja training academy.  The students are hand-picked from countryside villages, where they are trained in the secret arts of espionage, stealth, and assassination. Riley is a quick learner, and when she graduates at the top of her class, she's assigned a special mission to infiltrate the castle of Prince Takayori to kill him and his family.  But as an undercover maid, she is treated well by the prince's family, and soon falls in love with his daughter. When her ninja clan realize that she's gone rogue, they organize a hit team to invade the castle and kill her.  But Riley is not so easy to eliminate.  Against overwhelming odds, she must use all of her special skills to overcome a superior force to save herself and her loved ones.