The lovers — none so subtly named Adam (Jim Sturgess) and Eden (Kirsten Dunst) — first meet as children who manage to forge a spiritual connection even if they're literally upside down from each other. Unfortunately, contact between the inhabitants of the two worlds is strictly forbidden by the dominant one, Up Top, which exploits the resources of its neighbor planet, Down Below. Connecting the two worlds is a massive tower owned by an exploitative megacorporation named — what else? -- TransWorld.
Ten years after their initial encounter, which ended with Eden apparently falling to her death, Adam is a lowly scientist working at TransWorld who has managed to invent an anti-aging cream made from the pollen of pink bees (really). He suddenly comes across the now grown-up Eden, who has no recollection of him thanks to a case of amnesia from her fall.
So he sets out to woo her all over again, a task made more complicated by the fact that the only way he can enter her world is to don gravity-defying anti-matter that inconveniently bursts into flame after a short time.
If you've managed to follow all of this so far, then you indeed might enjoy the undeniably clever otherworldly setup for what otherwise is a fairly pedestrian love story. The writer-director produces many impressively striking images, many of them without the benefit of CGI effects, to render his fantastical setting. Particularly impressive is a virtuoso set piece involving a flaming Adam desperately propelling himself into an upside down body of water.
But despite their dual-worlds environment, the central characters ultimately are too one-dimensional to sustain our interest. Sturgess overplays the puppy-dog charm, while Dunst wears her natural radiance like a comfortable overcoat.
The film does manage to spring to life with every appearance by Timothy Spall as Adam's friendly but ill-fated co-worker. The veteran British actor delivers a wonderfully ebullient and moving turn that lends a genuine humanity to the otherwise overly contrived and mechanistic proceedings.
"Upside Down," a Millennium Entertainment release, is rated PG-13 for some violence. 100 minutes.
Motion Picture Association of America rating definition for PG-13: Parents strongly cautioned. Some material may be inappropriate for children under 13.