Raised by the Pope to become the perfect spy, she is sent to steal a powerful ducal family’s heirloom. But after taking a potion meant to shrink her body, something goes wrong and she turns into a five-year-old child. With death awaiting her if she fails the mission, she desperately searches for a way to survive, only to be unexpectedly adopted as the duke’s youngest daughter. She plans to use her new position to find the heirloom and leave before anyone discovers the truth. But as her new family treats her with genuine warmth despite sharing no blood, escaping becomes harder than she ever expected.