Su Tian, an orphan herself, sought to save the orphanage that had provided her with warmth since childhood. Because of her striking resemblance to Murong Xue, the adopted daughter of the Murong family, she transformed into a "sea queen," ensnaring all the fish in Murong Xue's fishpond and turning them into substitutes for the wealthy young men of the city. She provided companionship and emotional support to the fish, who in turn repaid her with the money she used to save the orphanage. Everything seemed to be progressing perfectly until Murong Xue returned home to find her fishpond dug up. An investigation revealed that the person who dug it up was none other than the Murong family's biological daughter—the very person who had saved Gu Beicheng, her primary target. Oh no! Now she was a substitute for her own substitute. To avoid losing everything she had, she resorted to any means necessary against Su Tian.
