Mariia Lukash, a daughter of the Professor of Medicine and a talented cardio-surgeon, performed an unsuccessful operation on a 9-year-old girl Maiia Gromova. The girl went into a coma, and Mariia was banned from surgeries and the participation in Maiia’s rehabilitation. Due to the efforts of Polina Maevskaia, an artful fiancée of Professor Lukash, Mariia quarreled with the father and dismissed from his hospital to become a district doctor of an ordinary children’s polyclinic. Mariia, lovingly called “our doctress” by her young patients, will have to help many people, find out the causes of the unsuccessful surgery, live through a disappointment with the man she loves and find her personal happiness.