Decades before zombies became a pop culture phenomenon and “The Walking Dead” transfixed television viewers, people around the U.S. and the world were mesmerized (and/or horrified) by the story of Carl Tanzler von Cosel and his beloved Elena Hoyos — who, like some denizens of “The Walking Dead,” didn’t remain among the living for long.

Undying Love: A Key West Musical

The stranger-than-fiction tale of Elena Hoyos and the demented “Count von Cosel” is to transfix Key West theater audiences through March 3.

The eerie tale unfolded in 1930s Key West. It was a time when Ernest Hemingway strolled the streets surrounding his island city home, fished for marlin offshore in the Gulf Stream, and worked on books that would become acclaimed around the globe as literary classics.

But even Hemingway couldn’t have dreamed up the story of the man who called himself “Count von Cosel” and fell deeply in love with a terminally ill girl named Elena Hoyos.

That’s because, while most people would expect Elena’s death to be the end of the pair’s love story, it was actually just the beginning.

The bizarre but true happenings — and the unsettling nature of the count’s death-defying passion — are chronicled for theater fans in “Undying Love: A Key West Musical.” It debuted on Valentine’s Day (which makes a weird kind of sense) at The Studios of Key West, a wonderful arts enclave at 533 Eaton St.

The macabre saga might seem like a peculiar subject to transform into a musical. But that’s what Key West author and musician Ben Harrison did. And he certainly had the expert knowledge to make it work, since he previously penned a nonfiction book, also called “Undying Love,” that chronicled von Cosel’s beyond-the-grave obsession with Elena.

When the shocking result of that obsession was discovered in Depression-era Key West, it sparked national news reports that both repulsed and fascinated avid readers — depending on how they interpreted the count’s activities.

Carl von Cosel Key West

In 1930s Key West, Carl Tanzler von Cosel became obsessed with the terminally ill Elena Hoyos — and the bizarre unfolding of his passion shocked the world.

Among the notable elements of Ben’s compelling show are projections and historical photos that evoke the island city’s isolation at that time, as well as the atmosphere surrounding the discovery and its aftermath.

It’s a full-scale theatrical production, with a cast of 10 actors — led by Amber Good as the enchanting Elena and Jamie Callahan as the fanatical von Cosel.

The darkly humorous show includes more than a dozen original songs, ranging from a risqué recap of the count’s actions to the eerie “La Boda Negra (Black Wedding),” which the delusional lover claimed Elena sang to him from her crypt. All written by Ben (whose wry and offbeat musical offerings have delighted audiences for many years), the tunes are rendered by a five-member orchestra.

Following its Feb. 14 debut, “Undying Love” runs for a limited engagement of just nine more performances through March 3. All begin at 8 p.m., and ticket prices range from $30 to $55 per person.

’Undying Love’ is the stranger-than-fiction tale of obsessive love, demented behavior and tropical mystery that you don’t want to miss,” reports a Studios of Key West article about the play.

More than 75 years after the tragic saga of von Cosel and Elena came to a close, Ben Harrison’s haunting, unforgettable production proves that — like the count’s twisted passion — some stories are definitely powerful enough to defy death.