‘Flesh and Blood’ on Masterpiece

Sundays at 10 p.m., beginning Dec. 19

Lust, greed, wrath, envy and pride are just some of the deadly sins that plague a seemingly happy family in “Flesh and Blood.” The mystery-thriller stars Imelda Staunton (“Harry Potter,” “Vera Drake”) and Francesca Annis (“Home Fires,” “Cranford”), who play close neighbors cast into a generational psychodrama.

Also starring are Claudie Blakley (“Grantchester,” “Cranford”), Russell Tovey (“Little Dorrit”), and Lydia Leonard as the grown-up children of Annis’s character, Vivien; Stephen Rae as a suspicious new addition to the family; and David Bamber (“Victoria”) as the detective who tries to work out whether an unfortunate incident was an accident or, in fact, a heinous crime.

Staunton, who is set to star as Queen Elizabeth II in the next season of “The Crown,” gives a slyly comedic performance as Mary, the family’s long-time next-door neighbor, whose life is devoted to gardening and trying to be helpful to Vivien.

Opening with emergency vehicles on the scene of a life-threatening mishap, the mystery for viewers is: Who has done what to whom?

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As D.I. Doug Lineham elicits the details in flashbacks, it all started innocently enough. Widowed a year and a half earlier, glamorous former salon owner Vivien invites her three children to their seaside childhood home for an important announcement: she has a new man in her life: Mark, a retired surgeon.

Wrapped up in their own complicated relationships, the children have mixed reactions. Career woman Helen is wary of Mark, perhaps because she sees romance as entirely transactional, which is how she treats her stay-at-home husband.

Jake is downright hostile to Mark, possibly out of guilt over the breakup of his marriage. Also, he’s worried about his inheritance, which may be his only hope for financial security.

Only Natalie, the youngest, is genuinely excited for her mom, likely because a fulfilling partnership is Natalie’s fondest wish. At the moment, she is in the fifth year of an aimless affair with her boss.

Then there is Mary’s opinion. Having no close family of her own, she has been a second mother to Helen, Jake and Natalie. A born sleuth, she conveys her serious doubts about Mark in the most elliptical way imaginable.

As for Mark, he dotes on Vivien and treats her to expensive surprises — plus he really wants to marry her. The question on everyone’s mind: Is he hiding something?