Dr. Martin Ellingham (Martin Clunes) is struggling to come to terms with fatherhood. The baby boy born to him and his estranged partner, Louisa Glasson (Caroline Catz), is about to change their lives dramatically. Doc Martin had planned to resume his high-flying career as a consultant in London. He had packed his bags and moved out of the surgery to make way for the new GP, Dr. Di Dibbs (Joanna Scanlan). However Dr. Ellingham begins to have serious doubts about the competency of the new GP after she misdiagnoses a patient, and dishes out prescriptions for totally inappropriate drugs. Dr. Dibbs realizes she has to go, and Dr. Ellingham agrees to resume duties at the surgery until a replacement GP can be found. With all the upheaval the doc is unprepared for a devastating personal blow with the death of Aunt Joan.