Watashi to Heika no Koukyuu Seizon Senryaku

The queens are gathered in the palace to determine the "beloved", the only queen of the young and wise emperor. Sonya, the 50th queen and the lowest-ranked among them, has a secret. Thanks to this secret, Sonya became the emperor's "beloved"...?
This is a story set inside the palace harem, with a "no return to death" policy!