In ‘Magpie Murders,’ double plots double the mystery

Who killed Alan Conway, and where is the last chapter to his final crime novel? Both puzzles need solving in Anthony Horowitz’s engaging adaptation of his 2016 novel.

Lesley Manville in "Magpie Murders" on "Masterpiece."Bernard Walsh/Eleventh Hour Films

There’s a mystery story within a mystery story in this new PBS “Masterpiece” miniseries, which makes it a twodunit, or, if you prefer, a whodunem.

Either way, “Magpie Murders” is an entertaining puzzle of a show whose two parallel but intertwined plots satisfy and, at moments, amuse, as they offer a clever meta-look at the whodunit genre. The prolific writer Anthony Horowitz, of “Foyle’s War” and “Midsomer Murders,” has adapted his own novel beautifully, so that his intricate conceit unfolds effortlessly across six episodes.

In the present tense, “Magpie Murders,” which premieres Sunday at 9 p.m. on GBH 2, is about the suspicious death of a famous, wealthy, and pompous crime author, Alan Conway (Conleth Hill, Varys on “Game of Thrones”). His Agatha Christie-like novels revolve around the cases of a 1950s private investigator named Atticus Pünd, who’s always at least one step ahead of everyone else. The reading public loves Pünd, a German gentleman whose small eyes seem to see right through to the truth of the matter. Conway, though, has highbrow aspirations, and he is quite done with the detective.

Just before his death, Conway turns in his final Pünd novel to his publishing house, including his editor, Lesley Manville’s Susan Ryeland. But the manuscript appears to be missing the final chapter, which, in a whodunit, is essential. Without the denouement, Susan notes, a whodunit is useless, all setup with no climax. And so Susan embarks on a search for that final chapter, touching base with Conway’s friends and family along the way, and in the process she finds herself also on a search for Conway’s killer.

As this story develops, Susan is reading Conway’s book, and we see its Pünd story develop, too. The series toggles between the two, from Susan’s investigation to Pünd’s, from the 2020s to the 1950s. In the book, Pund, played by Tim McMullan (“Foyle’s War”), is trying to solve at least one murder, the murder of the much disliked Sir Magnus Pye, possibly more. There’s a chance that the book may contain clues about the fate of its author, and Susan is alert to that possibility. Meanwhile, her own life is getting complicated; she has been invited to accept a new and more powerful job, her estranged father is ill, and her boyfriend has an unpleasant surprise for her.

Unlike most of the crime shows we see these days, “Magpie Murders” is light — both well-lit and not ponderous — and it’s not trying to dredge up the worst of human nature or trigger an existential crisis. It’s a “Masterpiece” mystery, and so it’s easy to watch, not least of all thanks to the always engaging Manville and a game cast, some of whom appear in both time frames. It’s good, twisty fun.

MAGPIE MURDERS

Starring: Lesley Manville, Conleth Hill, Tim McMullan, Andreas Logothetis, Daniel Mays, Pippa Haywood, Matthew Beard, Karen Westwood, Harry Lawtey, Dorothy Atkinson

On: GBH 2

Sunday night, 9-10