The superiority of “Foyle’s War” isn’t based on the detective stories, which are as formulaic as those in any other British period mystery and sometimes downright silly. (In Sunday night’s episode a suspect, asked when he last saw the murder victim, mutters: “Well how quaint. Very Agatha Christie.”) It’s based in part on the astonishing level of historical detail and atmosphere that the show’s creator, Anthony Horowitz, and his team have brought to the show’s milieu — the town of Hastings, on the south coast of England, during World War II — and on brisk, literate scripts.

Just as important, if less celebrated, is Michael Kitchen’s quietly compelling performance as Christopher Foyle, the extremely buttoned-down but testy police inspector whose passions for justice and tolerance animate the stories, and the easy chemistry among him and his two foils, Anthony Howell as Sergeant Milner and especially Honeysuckle Weeks as the steadfast driver Samantha Stewart.