Quick: A loved one is in a deep coma. What to do? You could obey the living will. Or, were you inclined to think like a Hollywood movie, you could sublet her apartment, wait for her spirit to show up and fall in love with the new tenant, then ask said spirit what it wants.
If this spirit is a smidgen like Reese Witherspoon's in the new romantic comedy ''Just Like Heaven," the answer will almost certainly be, ''I want to live!" Directed by Mark Waters (''Mean Girls"), the movie wants all you girls to know that should medical misfortune come your way, just hold on. Your soul will find your soul mate, then love will set you free.
Witherspoon plays Elizabeth, a meticulous go-getter physician in San Francisco. When she's not saving lives during 26-hour rotations, Elizabeth is stealing catnaps in the staff lounge, dreaming she's in a vast, softly lit Eden that could be mistaken for a Sarah McLachlan video. The women doctors in relationships speak to her in sighs (''You're so lucky that all you have to worry about is work"), as though her singleness has made her disabled. All her sister (Dina Waters) wants her to do is get a man, which Elizabeth is about to do when a truck hits her.
Mark Ruffalo is David, the sad-sack widower who moves into Elizabeth's gorgeous apartment after her accident. In no time he turns her Pottery Barn into a frat house so unkempt that Elizabeth comes all the way from limbo to insist he spruce up the place. What Elizabeth doesn't know is that she's an apparition. David's not sure, either. Drunk and depressed, he hires ghost-busters and an exorcist in a futile attempt to get rid of her. Eventually, Jon Heder (of ''Napoleon Dynamite" fame), playing an occult bookseller with a sixth sense, is called in to confirm that Elizabeth is not a figment of David's loneliness. She's a lost soul who doesn't remember who she is. And the movie concocts shenanigans as she and David try to figure out who she was.
Ruffalo seems stuck in gimmicky romances, having gamely agreed to love the 13-year-old trapped in Jennifer Garner's body in ''13 Going on 30," Gwyneth Paltrow's flight attendant in ''View From the Top," and Jennifer Aniston as the possible daughter of the lovers in ''The Graduate" in the upcoming ''Rumor Has It." He can be a fierce actor, but in comedies, he's not a leading man, he's a puppy. Yet he and Witherspoon demonstrate screwball-comedy teamwork, with him providing the laid-back bafflement and her bringing the pluck.
Her zip is contagious, which is why none of the disdainful testimonials from Elizabeth's co-workers and neighbors accusing her of being a one-track-mind drip seems accurate. Elizabeth is sociable, supportive, kind, and, above all, played by Reese Witherspoon. But the movie is determined to make this woman out to be a soulless climber who cared too much about her career and must be set straight. (I don't know many 30-ish doctors who are encouraged to have time for much else.)
Nonetheless, ''Just Like Heaven" suggests that a post-coma Elizabeth might understand what life is truly all about. Of course, if being alive means having to live in this movie, maybe she was better off the way she was.
Wesley Morris can be reached at email@example.com.