On Starz, the return of da Vinci, comic-book hero

Leonardo da Vinci is one of those impossibly gifted giants whose life was so remarkable, yet so full of mystery, it has inspired some seriously wacked-out theories.

Dan Brown had da Vinci enmeshed in a millennia-old conspiracy hatched by the Catholic Church.

There's plenty of the same off-the-wall madness in Da Vinci's Demons, writer-producer David S. Goyer's delirious TV drama that returns for a second season 9 p.m. Saturday on Starz.

Off-the-wall?

Saturday's episode opens atop Machu Picchu (in present-day Peru) where holy men in terrifying masks are preparing to decapitate Leo as a sacrifice to the Incan sun god. Huh?!

OK, let's come back to that.

Da Vinci's Demons is a thrilling adventure story full of comic-book heroism, violent intrigue, and wild sex worthy of The Borgias - and enough crazy inventions to shame MacGyver.

British thesp Tom Riley (Monroe, Lost in Austen) stars as the eccentric Florentine artista who can't sit still, so brimming is he with ideas, plans, theories, memories - and enough charisma to burn up a whole city.

 "My impression of da Vinci was only about his art, his brushstrokes. I didn't expect a man who was antiauthoritarian, rebellious, and heretical," Riley said in a phone interview. He said he really wasn't aware of the full extent of da Vinci's brilliance.

"Tom Stoppard . . . once told me being a genius is being able to sit at the top floor of the house without having to use the stairs while everyone else is at the bottom trying to figure out how to put one foot in front of the other," he said. "Da Vinci just saw things faster than everyone else."

There's one thing our TV da Vinci can't quite figure out: Love.

The man is hardly shy with the girls, but he falls fast and falls hard for the aristocratic Lucrezia Donati (Laura Haddock).

"She's a puzzle to him," said Haddock (Upstairs Downstairs). "She's fascinating to him because she's one of the only things he can't work out."

So, about those Incans?

In the first season, Leo discovers a millennia-old secret brotherhood called the Sons of Mithras, a mystical cult that prizes esoteric knowledge. They also are the authors or guardians (we're not really sure) of one of humankind's greatest treasures, The Book of Leaves, which contains mind-blowing truths. Leo is determined to find the book.

Goyer laughed when asked about the book. "Indiana Jones needs . . . the crystal skull. The hero needs to quest for something," he said on the phone.

Standing in Leo's way is the despotic Pope Sixtus IV (James Faulkner). He too wants to find the book, but only to suppress it.

The season ends with da Vinci racing to reach South America where he thinks The Book of Leaves is hidden. ("Da Vinci never went to South America as far as we know," Goyer admitted.)

Will Leo find the book?

Wait, we're thinking too far ahead: How is Leo going to survive those scary Incan priests?

Da Vinci's Demons

9 p.m. Saturday on Starz.EndText

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