A stomach bug sweeps through Portwenn. Martin creates mass panic by declaring it's the swimming pool, and then infuriates the locals by blaming the village water supply. Meanwhile, plumber Bert Large is making a mint off his new business: bottled water.

Martin fires his receptionist and informs the locals that they can no longer use his waiting room as a social center. In return, the villagers shun him, the cafe won't serve him, and patients cancel their appointments.

Doc Martin makes a bad impression on one Portwenn resident before he's officially hired. Things go downhill from there after he casts a pall over a local festival and gets punched in the nose.

Martin's estranged parents come to Cornwall for an icy reunion with their only son. His father sneers at Martin's small-town status and his mother barely speaks. But as the real reason for their visit comes to light, Martin reveals an unseen side.

A Salvation Army worker arrives in Portwenn to trace a missing woman, and the constable's checkup has surprising results that could impact his upcoming nuptials. Danny asks Louisa to move in with him, but she feels ambivalent.

Bird-watchers in search of a rare species disturb the peace. Martin may lose his receptionist, is told to brush up on his people skills, and Louisa's father arrives unannounced.

Martin has a new receptionist and a new problem: Louisa's ex has come home to Portwenn. Meanwhile, Martin detects signs of dementia in an elderly patient and learns the shocking reason for a fisherman's history of injuries.

The local constable asks Martin to be best man at his wedding, but the doctor flatly refuses. The stag weekend in the woods ends up going terribly wrong; however, Louisa is relieved by the outcome.

(Aired in the U.S. as "The Admirer") Romance is in the salty air of Portwenn: Doc Martin is pursued by a glamorous divorcée. Aunt Joan is wooed by a handsome artist 30 years her junior.

(Aired in the US as "Movement") Taking Doc Martin's advice to "make some life changes," Bert Large abandons plumbing and opens a restaurant. Soon Portwenn is plagued by an outbreak of food poisoning.