Perverse necrophiliacs looking to "Just Like Heaven" for a hilarious, death-affirming, heart-stopping good time will be sorely disappointed. Despite the tempting promise of ghost-on-man sex, the new romantic comedy starring Reese Witherspoon and Mark Ruffalo coasts for as long as it can on the charm of its leads before failing under the weight of its hastily thrown together plot.

Like "Grey's Anatomy" meets "Ghost," the movie begins with Elizabeth (Witherspoon), a frantically busy young doctor. Seemingly addicted to caring, Elizabeth wastes so much time on caring for patients and giving solace to the sick that she doesn't have time for romance. Poor career-driven Elizabeth. How do Hollywood movies treat such upwardly mobile female characters? Within 10 minutes, Elizabeth gets hit by a truck. Take that.

David and Elizabeth bicker like an even odder "Odd Couple." She doesn't like how much he drinks. He doesn't like how she keeps appearing in his bathroom when he gets out of the shower. It's not a match made in heaven, but in the process of trying to uncover her identity, they realize that they have a lot in common. Having seen the movie, I don't recall much that they have in common except that he's the only person who can see her, but if the twinkly music tells me that they're falling in love, how bitter would I have to be to disagree? The only problem is that Elizabeth may not be quite as dead as she seems to be.

Here's the part where I go into a spoiler of a major plot point that's revealed around a third of the way into the movie, so feel free to tune out.

Somewhere in the United States, there's a fundamentalist religious group that's gonna jump all over "Just Like Heaven." Elizabeth, you see, wasn't killed by that errant truck. She was just knocked into a coma. The doctors all say that her vital signs suggest that she's in a vegetative state. Elizabeth had already signed a Do Not Resuscitate order and the plug is going to be pulled. The problem is that as David very well knows, Elizabeth's spirit is very much alive and very much wants to live. The DNR, which seemed like such a good idea when she was alive, suddenly seems like an abomination, like true murder. None of the people affiliated with "Just Like Heaven" are politically conservative, but their movie is a delightful fictional representation of the Terri Schiavo case, slanted far to the right. That fact gnawed at me as I watched the movie, particularly when one character literally mentions a belief that regardless of what the machines say, they believe that Elizabeth's soul is still attached to her body.

So that bugged me a little bit and then I was bugged by the idea that the film was punishing a woman in her upper-20s for prioritizing her job (and healing the ill) to getting laid and making babies. But those ideological concerns mostly hit me after I'd dismissed the movie for other reasons.

"Just Like Heaven" shoots ahead at a breakneck speed, never pausing for developing characters or deepening relationships beyond a few quick gags. There isn't a single bit -- humorous or otherwise -- between the two leads that hasn't been done before and better in other haunted comedies like "Ghost," "Truly, Madly, Deeply," "Return to Me," "All of Me," "Heart Condition," "Chances Are," "Always" and "Heaven Can Wait."

The movie is a pastiche of quickly assembled and just-as-quickly discarded familiar moments. For a little while, Elizabeth gets a kick out of walking through things and appearing half-in and half-out of objects. Almost like she knows it isn't funny, she stops doing it almost immediately. Then there's one sequence where Elizabeth inhabits David's body and turns him into her puppet. It produces more laughs than any other scene in the movie, but it looks like it was hard work for Ruffalo (not in the same physical comedy league as Steve Martin, who played the gag for the duration of "All of Me"), so they don't do it again.

Peter Tolan and Leslie Dixon are credited with the script, but the wheel-spinning madcap frenzy and somewhat questionable messages about feminism are pure Dixon, who was responsible for the very similar "Outrageous Fortune" and "Overboard." The funny thing is how fresh director Mark Waters seems to think it all is. He treats ever cliched bit like gold and he and cinematographer Daryn Okada shoot San Francisco as if the city had never been the setting for a romantic movie ever before.

Despite the potential for subversion in the spectral subject matter, this is a distressingly conventional turn for Waters, whose slightly twisted sensibility made "Mean Girls" and "Freaky Friday" into surprise treats.

Audiences, though, will flock to watch Witherspoon, who doesn't break a sweat in delivering silver-tongued barbs and wide-eyed wonderment. Stumbling, bumbling and doing one double-take after another, Ruffalo tries to stretch beyond his standard tortured, mumbly persona and his indie take on the genre is refreshingly different from Witherspoon's mainstream approach. They just never develop chemistry as a couple.

Heder leads the gang of quirky supporting characters, but "Napoleon Dynamite" fans hoping for much of their cult hero will be disappointed with how little he has to do with the story.

"Girlfriend in a coma, I know/I know -- it's serious," so says The Smiths' song. Maybe not so serious, but unfortunately it isn't all that romantic or funny either.