All of the wit in Seth Grahame-Smith’s previous mash-up — the turgid, entrail-splattered “Abraham Lincoln: Vampire Hunter” — could be found in its title. At least that counts for wit if you’re still splitting your sides over the author’s tyro bestseller, “Pride and Prejudice and Zombies.”

So here is Grahame-Smith’s new novel, “Unholy Night,” which purports to give us the hitherto untold history of — wait for it — the Nativity of Jesus Christ, the Three Wise Men, Herod’s Slaughter of the Innocents and the Holy Family’s Flight into Egypt: a New Testament knee-slapper if ever there was one. I approached the novel with all the enthusiasm of a Skid Row habitue entering a Salvation Army meeting.

I left a convert.

Those with weak constitutions and lofty literary standards be warned: Grahame-Smith has forsaken neither graphic gore nor gleeful historical and religious revisionism.

This is a novel in which the hero, an unrepentant thief seeking refuge in a stable, introduces himself and his accomplices as follows: “Joseph? Mary? My name is Balthazar. This is Gaspar . . . this is Melchyor. We don’t want to hurt you . . . we’re just looking for a place to rest. But, Joseph? if you don’t put that pitchfork down, I’m going to take it from you and stab you to death in front of your wife and child. Do you understand?”

“Unholy Night” by Seth Grahame-Smith. (Grand Central Publishing)

If you can get past the notion of a pitchfork-brandishing Joseph (yes, that Joseph) in a manger (yes, that manger), you’ll find “Unholy Night” a surprisingly touching and sweet-natured tale of derring-do, magic and salvation, based very, very, very loosely on events familiar to many from Sunday school or, perhaps, Monty Python’s “Life of Brian.”

Along with his fellow ne’er-do-wells, Balthazar, a legendary Syrian thief known as the Antioch Ghost, escapes from wicked King Herod’s dungeon by murdering three wise men and donning their robes.

In Bethlehem, the thieves take up with another trio fleeing Herod’s soldiers: woodworker Joseph, his 15-year-old wife, Mary, and their newborn son. All witness and barely escape Herod’s horrific massacre of infants and toddlers, after which Balthazar agrees to escort Joseph and his family to safety in Egypt. Herod’s soldiers give chase, along with Roman troops led by an ambitious young man named Pontius Pilate, and a wicked Magus in the employ of Emperor Augustus Caesar.

Grahame-Smith manages to have great fun with this material while remaining (mostly) true to its original narrative. His Herod is truly a villain for the ages; Pilate, at 22, is already a conflicted truth-seeker. The Holy Family is depicted with warmth and humor. It’s left to Balthazar, still guilty over the death of his little brother decades earlier, to bear the weight of modern cynicism and vengefulness, while remaining open to redemption. He also brandishes a mean sword.

This novel has a high body count, although it’s nothing compared with its source material. In “Unholy Night,” Grahame-Smith manages the neat trick of providing a satisfying and moving new ending to a story that has been recounted untold times.

One is tempted to call it a miracle.

Hand’s new novel for young adults, “Radiant Days,” about poet Arthur Rimbaud, has just been published.

UNHOLY NIGHT

By Seth Grahame-Smith

Grand Central. 307 pp. $24.99