Among the denizens of Portwenn are Louisa (Caroline Catz, The Vice), a school teacher who is a love interest for Martin, Bert (Ian McNeice, Doctor Who, Rome), a handyman for all occasions, Al (Joe Absolom, EastEnders), Bert's computer savvy son, Mark (Stewart Wright), the eager and sweet local cop, and Elaine (Lucy Punch, The Class, Dinner for Schmucks), his inept assistant who he cannot fire without risking being running out of town on a rail, should a rail be found. Some of these people leave, and new ones arrive, but I won't elaborate further, as I wouldn't want to spoil anything.
It's honestly a very charming series. There is comedy, and also some heart. "Delightfully quirky" is how the Los Angeles Times describes it, and it would be hard to find a better adjective. Confident in what it does, Doc Martin is a refined formula that provides much enjoyment. The humor isn't very edgy, nor the drama too melodramatic, but it is definitely an enjoyable way to spend a few hours.
As for bonus features, there are none to speak of. Just a few photo galleries, cast trivia, and filmographies, things easily found online, that don't really add anything to the experience. But, like many releases from overseas, it's nice enough to have the episodes to watch, that anything else isn't really necessary anyway.
Doc Martin will return to ITV and PBS soon, but in the meantime, be sure to buy Doc Martin Collection: Series 1-4, on sale now.