Mary Hatching's mother died in a car crash, leaving her father too distraught to care for her. Nicholas's cousin Gaston proposes that he place Mary in the care of Queen Rachel and King Adam, believing it would ease their grief over the loss of their daughter. King Adam and Queen Rachel immediately take a liking to Mary. Although King Adam has banned gardens, Mary, who adores them, decides to create her own hidden garden. Meanwhile, King Adam and Queen Rachel uncover some hidden truths about their own history.