Adam is a seemingly ordinary guy in a very extraordinary universe. He lives humbly trying to make ends meet, but his romantic spirit holds on to the memory of a girl he loved once upon a time from another world, an inverted affluent world with its own gravity, directly above but beyond reach... a girl named Eden. Their childhood flirtation becomes an impossible love. But when he catches a glimpse of grownup Eden on television, nothing will get in the way of getting her back... Not even the law or science!
The film's setting is magnificently beautiful, there are a lot of stunning ideas and images and the main story is good enough to make the two-planet world look real. The one and the only one flaw of the film is that it pretends to be a sci-fi film rather than a fairy-tale in an unusual setting. If you judge it as a sci-fi you will find a lot of "how could it be" things that tear the imaginary world apart. The actors are great and it is fun to see Spall as a protagonist friend rather than foe. Both Sturges and Dunst are wonderful. So if you want to watch a sci-fi film you better avoid "Upside Down". This is a love story set in the fantasy world. No more, but no less.