What, exactly, is normal?

In Andrew Lippa, Marshall Brickman and Rick Elice’s musical adaptation of the cult classic T.V. show “The Addams Family,” “normal” gets an entirely new definition. Graveyards behave playfully and the closet monster is childhood a friend. In the production that just opened at Spreckels Performing Arts Center, the set is draped in black and cobwebs, and the Addams family’s twisted sense of perspective leads to some very quirky humor and marvelous opportunities to let loose an echoing evil laugh.

In a crumbling mansion, with a butler who resembles Frankenstein’s monster and the disembodied hand of “Thing” emerging to dispense helpful objects, the Addams’ are nothing if not unique and fascinating. Their joyful carousing through the cemetery is interrupted by terrifying news, however. Wednesday Addams has fallen in love with Lucas, an ordinary boy from Ohio. We learn that their chance meeting (while she was hunting with a crossbow in Central Park) turned into a whirlwind affair, and it is time for the dreaded introduction of the young lovers’ parents.

How will Wednesday convince her family that Lucas is right for her, when they consider fresh flowers tasteless, and are accustomed to specters drifting through dreary stone halls?

Filled with wacky one-liners – as when Lucas blurts out, “I can be impulsive, I just need to think about it first” - this macabre coming-of-age story is a spectacle of swashbuckling duels and heartfelt connections. Director (and Petaluma resident) Carl Jordan has molded the script’s pandemonium of eccentric characters into an ensemble of strong singers who are able to find common ground.

Balancing the original TV cast’s mannerisms with a contemporary, edgy mood, Morticia (Serena Elize Flores), Gomez (Peter T. Downey), Wednesday (Emma LeFever), Pugsley (Mario Herrera), Uncle Fester (Erik Weiss) and Grandma (Tika Moon) all coast through the ups and downs that a family faces when the children grow up. Ultimately, they discover that their relationships must change in order to survive.

Weiss as Uncle Fester is charismatic and outlandish, capering with precise comic timing and an innocent smile. His banjo serenades to the moon are adorable, even if they jeopardize Wednesday’s plans to present an ordinary family to her potential in-laws.

Michella Snider’s choreography draws on a variety of eras, giving the ghostly chorus-line of “ancestors” a series of angular and purposeful gestures. The songs, by Andrew Lippa, have an oddly cheerful gloom to them, such as “Death is Just Around the Corner,” with a capering Grim Reaper twirling his scythe. Music director Lucas Sherman and the orchestra sizzle with tango-flavored music, and (of course) the signature television theme, complete with snapping fingers.

“The Addams Family” is a cauldron of ghoulish fun and a delightful twist on the traditional romantic musical, arriving (ghosts and tombstones in tow) just in time for Halloween.