Jocelyn Grant, a modern military doctor, travels through time to the Kingdom of Aethel. She becomes the true heiress of House Everpeace. She is forced to be a substitute bride for the false heiress and marry the crippled prince. Jocelyn discovers she carries a portable medical space. While treating the prince, she takes down the scheming false heiress and uncovers the shocking case of Consort Livia swapping the prince at birth.