Turns out they got a good price on that rambling Victorian for a reason: It's the featured stop on a popular "Murder Tour" in the City of Angels.
The real estate agent didn't see fit to tell the Harmons that everyone who has ever lived there met a violent end. They had to find that out from the spooky Blanche DuBois-type who lives next door (Jessica Lange).
With the housing market in the dumps, the Harmons can't unload their chamber of horrors.
Soon they're besieged by the emotionally disturbed, the developmentally disabled, the physically disfigured, and other creatures who defy explanation.
There is, for example, a figure sheathed head to toe in a shiny black bondage suit. We're pretty sure he/it has impregnated Mrs. Harmon. Don't even get us started on the hideous monstrosity in the basement.
Even the most benign-seeming characters carry wickedly toxic luggage. And in this vile villa, it's impossible to tell the living from the dead, the haunted from the haunting.
The series carries a "mature audiences only" rating, and each episode carries an additional warning for two or more of the following: indecent language, explicit sexual activity, and graphic violence.
Faced with this sick spectacle, viewers have two options: shield their eyes and reach for the remote, or fasten their seatbelts. Increasingly they are harnessing down for the ride.
Last week's episode, the first of a two-part Halloween extravaganza (the conclusion is Wednesday night), saw viewership jump 15 percent to 3 million.
Precisely what is it that they're experiencing in this series produced by Ryan Murphy and Brad Falchuk?
"It's all the horror of being in a relationship and being in a family and being in a marriage," says AHS star McDermott. "It's a metaphor."
Hmm, interesting theory. Anyone else?
"It's the haunted-house genre taken to an extreme," ventures Levina. "Everything is coming at them from inside the house. It's terror internalized.
"We've seen these type of stories in films since 9/11. We're living with terror that you simply can't solve, in an America where things are going terribly wrong."
If you have the stomach for it, American Horror Story works pretty well as pure entertainment. (On Monday, FX gave AHS an early renewal for next season.)
"It's a very well-done, even innovative way to tell a scary story on TV," says Ken Tucker, editor at large at Entertainment Weekly and former TV critic at The Inquirer, via e-mail. "On the other hand, it's one of the creepiest, most depressing shows to come along since The Real Housewives of New Jersey.
"Jessica Lange has the tone down best, and when Jessica Lange is your barometer of emoting, you know the show might go over the top at any moment."
Over-the-top is the specialty of the house for producer Murphy. His TV creations have veered from the catty and funny high school soap Popular to the emphatically outrageous adult plastic surgery drama Nip/Tuck to the high school show choir sensation Glee to the gnarly, envelope-tearing American Horror Story.
Not an easy guy to pigeonhole.
"Ryan gets bored easily," says Dylan Walsh, who starred in Nip/Tuck. "Before he's done, he will have created some of the most unforgettable series in TV history. And they'll all be different."
Calling American Horror Story "different" - that's definitely an understatement.
Contact staff writer David Hiltbrand at 215-854-4552, firstname.lastname@example.org, or @daveondemand_tv on Twitter. Read his blog, "Dave on Demand," at www.philly.com/dod.