From MangaHelpers:
26-year-old Tamiya Seiji is a doctor-in-training whose residency is not going all that well. One day, he meets a teenage girl named Ikumi, who dreams of being a bread baker. They begin to meet regularly, for him to taste-test her new breads. However, Ikumi has a secret. She is a child genius, who became a famously skilled surgeon in America. She vanished from the medical scene, moving back to Japan to become a high school student and bake bread. At this point in both of their lives, meeting one another might be the best thing that could have happened.