Michael Sheen and David Tennant in Season 2 of Amazon's "Good Omens."
CNN  — 

Winging back to Amazon more than four years after its debut, “Good Omens” relies on the genial interactions of its cast in a whimsical trip filtered through the strange millennia-spanning relationship between an angel and demon. The plot, in fact, is practically irrelevant in this six-episode second season, other than providing the excuse for Michael Sheen and David Tennant’s heavenly reunion.

At times coming across like a cheekier version of “History of the World” with representatives of Heaven and Hell as guides, the adaptation of Terry Pratchett and Neil Gaiman’s novel again features Gaiman (“The Sandman”) as a producer along with Douglas Mackinnon, who directed all the episodes.

Although Sheen’s angel Aziraphale and Tennant’s surly demon Crowley have seemingly settled down on Earth (specifically, in London), the series enjoys an unfettered run of space and time, visiting Victorian England or World War II or biblical times at the drop of a halo.

This time, the story centers on the archangel Gabriel (Jon Hamm, exhibiting his sometimes-underappreciated comedic chops), who shows up at Aziraphale’s doorstep naked and completely confused, having no memory of who he is or how he got there.

That rather unsettling turn of events garners the attention of representatives from both Heaven and Hell (as depicted here, each mired in their own versions of frustrating bureaucracy), forcing Aziraphale and Crowley to cooperate as they try to get to the bottom of what happened and stave off the potential consequences of Gabriel’s situation.

Jon Hamm as the archangel Gabriel and Michael Sheen as Aziraphale in "Good Omens."

“Good Omens” is light to the point of weightlessness, but it’s consistently fun, and its silly streak is nicely balanced by an an underlying sweetness and warmth stemming from the unlikely bond shared by its mismatched central duo. Besides, if an angel and demon can bridge the yawning gap between them, isn’t there a bit of hope for all of us?

Beyond Sheen, Tennant and Hamm, the show is stocked with fine actors, among them Miranda Richardson as a particularly ill-tempered demon eager to stir up trouble; Derek Jacobi as the Metatron, a.k.a. the voice of God; and Shelley Conn as Beelzebub.

Granted, streaming services have a recent habit of keeping fantasy and sci-fi bets alive out of almost what amounts to stubbornness in the face of mediocrity, with Apple’s “Foundation” and Netflix’s “Sweet Tooth” having recently returned for second seasons and Amazon’s “The Wheel of Time” due for an encore in September.

“Good Omens,” by contrast, is a mostly delightful little diversion with an amusingly irreverent tone. That’s not to say there was a pressing need for another season, only that it’s nice to have one with a show that, to borrow from the band that sang about sympathy for the Devil, really does have time on its side.

“Good Omens” premieres its second season July 28 on Amazon’s Prime Video.