Vampire Sisters 3: Journey to Transylvania (2016)

Mihai Tepes kept it from his vampire family as long as possible, but prepared the defense of his half-human baby son Franz, a rare cross just suited as successor for the Transsylvanian queen of the black castle, Antanasia. Alas, his budding junior daughter's clumsy first attempts to use magic turn him and his wife Elvira into babbling idiots. So the queen can easily steal the boy, leaving only daughters Dakaria and Silvania to rescue him, leaving their human knave protectors Ludo and Jacob to babysit their parents. Dakaria flies thereto and teams up with befriended vampire rock star Murdo, but starts doubting if Franz wouldn't be well off as adopted heir to the throne. Silvania seeks help from vampire nurse Ursula, but she's pregnant and deputizes her unsuspecting devoted husband, clumsy vampire hunter Dirk van Kombast, who ignores he's helping a vampire family. At least the castle staff are fools.