Elizabeth Winston, the true heiress of the wealthy Winston family, was swapped at birth and grew up in poverty under the cruel care of her adoptive parents, who named her Lily Baker. As an adult, desperate and struggling to survive, Lily sees a missing cat notice posted by the Winstons. She takes in a stray cat that closely resembles the Winstons' lost purebred Maine Coon, names him Oscar, and enters the Winston estate under the guise of a cat sitter.Inside the estate, Lily encounters the greedy and malicious butler Sebastian, who harasses her and tries to frame her. During a struggle, Lily discovers a music box engraved with the words "To my little star — K," which connects to a star-shaped birthmark on her shoulder. She begins to suspect she may have a blood connection to the Winston family.Charlotte, the fake heiress, initially treats Lily with hostility. But after Sebastian's true nature is exposed, the two gradually reconcile. Lily shares her secret about Oscar being a fake with Charlotte, and Charlotte in turn confesses that she is not a true Winston. However, Charlotte's biological parents (the gardener and driver) overhear this secret and publicly expose Lily for using a fake cat, hoping to drive her away. But Lily has prepared thoroughly — she has carefully dyed Oscar's fur to perfectly match the original cat and produced official registration records as proof, turning the accusation against them.Meanwhile, Alexander, the Winston family's eldest son and Lily's biological brother, plots to eliminate Lily to secure his inheritance. He kidnaps both Lily and Charlotte. But Lily has secretly installed a micro-camera inside Oscar's bell, which streams Alexander's crimes directly to Mr. and Mrs. Winston. The truth is revealed. Lily reunites with her biological parents, becomes the family heir, and persuades them to formally adopt Charlotte.
