The road to a good screen adaptation of a beloved book is paved with good intentions, but often littered with bad executions. But if a show were made of pure good intentions, it would be Amazon’s Good Omens, which is a show eager — even desperate — to do justice to its source material. And thanks to the delightfully absurd performances by stars David Tennant and Michael Sheen and an irreverent Monty Python-inspired touch from director Douglas Mackinnon, it just about succeeds.

Neil Gaiman, who co-wrote the 1990 novel with the late Terry Pratchett, writes and showruns the Amazon miniseries, in his first time ever acting as a showrunner for a TV production. Gaiman is no stranger to TV, having frequently written for shows like Doctor Who, Babylon 5, and adaptations of his own novels like American Gods and Neverwhere, but there is a starry-eyed enthusiasm to Good Omens that feels like Gaiman is out to prove something. You can imagine the burden that Gaiman is carrying with his miniseries adaptation of the book — Pratchett and Gaiman had planned to adapt Good Omens as a movie for years, but after Pratchett’s death, Gaiman had refused to develop the adaptation solo. But upon receiving a posthumous letter from Pratchett giving Gaiman his blessing, he changed his mind.

Gaiman’s intensely personal relationship with Good Omens perhaps prevents him from approaching the series with anything but a fastidious loyalty to the source material, and an impatient need to impress. As such, the first episode of the series is an incredibly plot-heavy first hour, racing through the first one-third of the book.

Appropriately titled “In the Beginning,” Gaiman and Mackinnon load the episode with the mythology and exposition stretching back to the beginning of Earth, when the uptight angel Aziraphale (Sheen) and the mischievous demon Crowley (Tennant) first meet at the Garden of Eden — Crowley having just successfully tempted Eve with the apple from the tree of knowledge of good and evil, and Aziraphale having given them the gift of fire in the form of a flaming sword. Though standing at opposing sides, they strike up a camaraderie over their pity for the defenseless humans that will last eons. This wary alliance — which we see in brief, glorious glimpses throughout history — finally becomes a full-fledged friendship when the two are faced with the imminent doom of Earth in the form of the Antichrist. When Crowley is tasked to deliver the Antichrist to be switched with the son of the U.S. Ambassador (Nick Offerman), he reluctantly carries out his task, unaware that a classic case of human error has flubbed the switch, resulting in the Antichrist landing in the lap of a sweet, local British couple. But with neither Crowley nor Aziraphale eager to see the world end in an epic battle between heaven and hell, they make a deal to try to avert the Apocalypse without their bosses knowing.

But despite the amount of material it covers, the first hour is still brisk because of Tennant and Sheen’s sublime chemistry. Tennant, who has the difficult job of acting behind sunglasses for the majority of the series, is pure rock-star charisma on a stick, all swagger and sex and fabulous hairstyles. But Sheen is next-level good, purity and sweetness radiating from his eyes and posture — somehow making his Aziraphale’s foppish, fussy nature seem completely endearing rather than irritating. Good Omens cleverly invests in Crowley and Aziraphale’s relationship, scattering sequences of the pair meeting throughout history and occasionally saving each other’s lives. A whole show could be made of just Sheen and Tennant’s characters getting into history (for you Doctor Who fans out there, there’s a fun nod to the Shakespeare episode). Their push-pull dynamic is as playful as it is stealthily romantic, something the show leans into as it becomes clear that their friendship is the heart of the series.

Unfortunately, the show isn’t as interesting when Sheen and Tennant aren’t onscreen. The show’s lively buoyancy gets a little deflated when it turns its focus to its supporting characters like Anathema Device (Adria Arjona), the eccentric descendent of a witch who prophesied the end of the world, and Newton Pulsifer (Jack Whitehall), a descendent of the witchfinder who burned Anathema’s ancestor and a sentient wet blanket. Despite their subplots being essential to the actual narrative arc of the series, the middle episodes devoted to them, and the other human characters Witchfinder Sergeant Shadwell (Michael McKean) and Madame Tracy (Miranda Richardson), nearly bring the show’s zippy momentum to a grinding halt. McKean and Richardson are at least amusingly ridiculous as a deluded misogynist and an absentminded medium/courtesan, respectively, but Arjona and Whitehall don’t lend much charisma to their thankless roles of the show’s closest things to straightforward protagonists.

As the fabled Antichrist, Sam Taylor Buck is perfectly capable in the role of a child whose innocent whims become the cause of worldwide mayhem. He and his friends (Alfie Taylor, Lan Galkoff, Amma Ris) admirably hold their own against the star-studded cast, but are inevitably overshadowed by Sheen and Tennant making a meal of the scenery. The four children’s adventures have the most potential to expand into an interesting subplot, but the show’s (understandable) fixation on Crowley and Aziraphale and (less understandable) focus on Anathema and Newton leave their story a little half-baked.

However, the expanded role of Jon Hamm‘s deliciously obnoxious archangel Gabriel is a stroke of genius. Hamm revels in playing the arrogant asshole who is carrying out the supposed will of God, whatever the cost of human life. Not only does it allow Hamm to deliver one of his best performances of cheery sadism, it gives us further insight into the inflexible realms of Heaven and Hell, which are run — for all intents and purposes — like corporate offices. The depiction somewhat flies in the face of Frances McDormand‘s languorous narration of the series as the voice of God, but it’s an entertaining new innovation on the part of the show.

Good Omens is, for better or worse, unapologetically British. Mackinnon gives an ambitiously surreal and yet purposefully cheap style to the series — inspired no doubt by Terry Gilliam, who was meant to direct the original film adaptation. There’s a heightened camp element to Mackinnon’s direction, compounded by the dry British humor, some of which gets lost in translation. The comedy feels like a victim of Gaiman strict adherence to the novel, whose 29-year-old humor feels a little creaky and out of place in the series. But despite Gaiman’s passionate attention to the minutiae, Good Omens is far from stuffy. Lackadaisical in tone and pace but packed to the brim with irreverent interludes and wacky segues, Good Omens may not be a revelation but it promises a good time with two heavenly stars.

/Film Rating: 7 out of 10