A romantic comedy requiring an audience to believe in a powerful love between two corporeally incompatible characters, "Just Like Heaven" detracts from its mission with cheesy effects, gaudy comic bits and lazy writing.

Those problems aren't enough to ruin the film's overall sweetness or to diminish the honest, moving performances of its two leads, Reese Witherspoon and Mark Ruffalo. But it's not hard to see that a C+ diversion such as "Just Like Heaven" could have been an A+ experience with more grace and discipline.

Loosely based on a novel called "If Only It Were True" by Marc Levy, the story finds Witherspoon's workaholic doctor character, Elizabeth, in a coma following a car accident. Her furnished apartment is sublet to a morose widower, David (Ruffalo), who drinks too much and soon starts having encounters with Elizabeth's spiritual emanation — not quite a full-fledged ghost, as she's on life-support systems.

Movie review

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"Just Like Heaven," with Reese Witherspoon, Mark Ruffalo, Donal Logue, Jon Heder and Dina Waters. Directed by Mark Waters, screenplay by Peter Tolan and Leslie Dixon, from the novel "If Only It Were True" by Marc Levy. 101 minutes. Rated PG-13 for some sexual content. Several theaters.

These meetings are a fun variation on old campfire stories about spooks clinging to their former dwellings and scaring newcomers. Elizabeth randomly pops up in one room or another, as nonplussed by David's presence as he is of her arrival. Then, suddenly, she's gone.

That touch of mystery is exhilarating. Director Mark Waters knows how to turn the gimmicky unknown into psychologically comic adventure, just as he did in 2003's "Freaky Friday."

But it isn't long before that instinct is superseded by more obvious and lowbrow sight gags, such as Elizabeth passing through objects and even into David's body at one point for a misguided lift from the Steve Martin comedy "All of Me." A tossed-off reference to "Ghostbusters" and undernourished supporting roles for Donal Logue and "Napoleon Dynamite's" Jon Heder are equally unfortunate. (Dina Waters fares much better as Elizabeth's sister.)

The script suggests destiny led to the meeting of David and Elizabeth, but that kind of gilding can't give what Ruffalo and Witherspoon give the movie through genuine emotional clarity. Against a lot of odds, they save "Just Like Heaven" from itself.

Tom Keogh: tomwkeogh@yahoo.com