A Discovery of Witches review – hide the sex and blood! The polite vampires are here!

Supernatural beings continue their epically passive-aggressive beefs as Sky’s fantasy saga flosses its fangs for a final season

Dry January? Austere new year? If this stretch of the calendar is about replacing indulgence and cheer with a cold slog, it’s fitting that it sees the return of A Discovery of Witches (Sky Max/Now), telly’s most conservative supernatural saga. Pour a herbal tea, put on a cardigan that does not sparkle, and head back to a world where mythical beings, unencumbered by time, death or physical laws, use this epic freedom to argue irritably among themselves.

This is the fantasy show that treats blood, lust and grotesquery as faux pas to be carefully avoided. It isn’t funny, sexy or scary, not because it fails at those things but because it refuses to attempt them. It also doesn’t think fantasy should be a gateway to anywhere. On the surface it’s about witches, daemons and vampires, but dig for subtext, search for the soul of the creation, and it’s about … no, it’s still just about witches, daemons and vampires.

Mainly, it’s about acting in a specific mode, familiar from a million earthbound terrestrial dramas shown at 9pm on wet Tuesday evenings, which is: vexed. Miffed. Positively cheesed off. A bit stressed. Many, many lines are delivered in portentous murmurs while the speaker inspects the middle distance or, in times of confrontation (“Nobody’s beyond reproach – not even YOU!”), through weakly clenched teeth. The chief beef is between a gang of compassionate Ws, Ds and Vs led by the show’s romantic protagonists – aeon-spanning vampire Matthew (Matthew Goode) and his increasingly powerful witch wife Diana (Teresa Palmer) – and the Congregation, a reactionary council dominated by smugly cunning vampire Gerbert d’Aurillac.

Gerbert is played by Trevor Eve, who knows his way around a drama that takes itself too seriously and is in his element here, often having fun with line readings by inserting a … colossal pause where the viewer, and indeed recognisable English idiom, least expects … it. His sidekick in the pursuit of mild evil: Owen Teale as senior witch Peter Knox, disgruntled and crass like a resentful divorcee. Even the arch villains are less awesome monsters than slightly annoying gits.

Anyway, where are we as the third – to some extent climactic – and final season begins? We’re around a long oak table in a luxurious French castle retreat and, although the characters in this show seem as if they could simply own a holiday home there, there is dark business to discuss. This is the HQ of vampire matriarch Ysabeau (Lindsay Duncan), where all three types of creature have gathered to plot their response to a rare and shocking killing at the end of season two. Millennia of passive-aggressive narking are about to come to a head.

Key to the ultimate resolution of the story will be Diana’s quest to find the lost pages of The Book of Life, a mystical tome carrying secrets that perhaps only she has the ability to unlock. That strand might not cohere very effectively as it winds along – it’s a magic book that fixes stuff and tells people things when the narrative requires it to – but it does prompt Diana’s last push towards self-actualisation. There’s a satisfying neatness in the way someone who began as a blushing newcomer steadily becomes the strongest player in the game.

Related: A Discovery of Witches series two review – vanilla vampire romp is a bloodless bore

The looming denouement also obliges Matthew to atone for the carnage he has wrought across the centuries, this being the dire consequence of the “blood rage” – basically, a catastrophic loss of manners, which is a big deal in this show. It has dogged him and his family, and may be connected to a series of murders in present-day Oxford. But there is a problem. One that has hampered A Discovery of Witches since season one, episode one: Matthew Goode plays this undead beast as clipped and inert, you cannot buy him as having unleashed any chaos. He’s aristocratic, but not in the classic vampire mould, ie, a parasitical outcast who envies feeling, fallible humans while his pale influence hovers half-seen over countless benighted generations. It’s hard to imagine Matthew having a strong view either way.

Matthew does, however, want to undo his clan’s bloodlust by harnessing genetics, an odd concession to reality that leads eventually to a showdown: Diana storms into the Congregation’s premises and demands to speak to the manager. Here, A Discovery of Witches finally finds its point: witches, daemons and vampires should renounce their rivalries, interbreed, live in tolerant harmony and forget all this eternal blood-war nonsense. Which is just as well, because no one seemed that bothered by it in the first place.