The Kings New Mistress

After a new queen falls ill, a physician announces that if the she were to fall pregnant, it would kill her. The king, thus, calls for a mistress who's children would be next in line for the throne.
Upon learning this, an aristocratic sorceress sends her two daughters to the royal court with a love potion and a plan. However, when jealous elder sister Veta decides to take matters into her own hands, their mother's plan quickly derails and both girls end up in grave danger.