Ep 4. Driving Mr. McLynn

Doc Martin season 4 episode 4, titled "Driving Mr. McLynn," features Martin Ellingham, a highly skilled doctor who deals with the peculiar inhabitants of the idyllic town of Portwenn, as he takes on a new challenge. During this episode, Martin gets called to visit a patient, but due to his lack of a driving license, he finds himself unable to use his car to get to the patient. In an effort to make it there quickly, he seeks the help of an old friend, Sean McLynn, to drive him to the patient's house.

Sean McLynn is an irritable patient who suffers from serious back pain and has refused to let any other doctor apart from Martin Ellingham treat him. After initially turning down Martin's offer to drive him, Sean eventually relents and agrees to take him to the patient's house in his taxi. However, Martin soon realizes that this will be no simple driving task as Sean's vision seems to be impaired, and he can barely see the road while he drives.

While on the road, Martin takes notice of Sean's odd behavior and slowly discovers that he is suffering from a dangerous illness that is affecting his ability to see and think. Determined to make things right and help Sean, Martin decides to diagnose and treat him right on the spot, while still in the moving car. As they race through the scenic countryside, Martin performs an unpredictable diagnosis that shocks even his considerable medical skills.

Martin simultaneously tries to avoid the police after realizing another passenger of Sean's taxi is carrying illegal contraband. Meanwhile, back in Portwenn, Louisa is dealing with scheduling issues at the school, and PC Mylow is seeing a change of attitude from the town's resident curmudgeon, Mrs. Tishell. Will Martin make it to the patient quickly to diagnose the illness and subsequently help Sean with the much-needed treatment? Will their taxi make it unscathed back to Portwenn, with a passenger who is slowly becoming too difficult to handle? Watch the episode to find out.

"Driving Mr. McLynn" is an engaging episode that showcases Martin's impeccable medical skills when pushed to his limits. The odd behavior of Sean adds to the drama and makes for some rather tense moments on the road. The episode also introduces some interesting subplots that delve into the daily lives of Portwenn's weird and quirky residents, adding more depth to the narrative. Overall, this episode is a testament to the excellent writing, directing, and acting seen throughout the show's four seasons.