Let me say this right up front: I love M. Night Shyamalan's vision and sense of storytelling. For most movie reviewers, he is the director they love to hate (and love even more to snark attack viciously). Once critically acclaimed (he won an Oscar for "The Sixth Sense"), he has been criticized for what some see as lazy screenwriting and what others think is an over-reliance on the twist ending. Slate's Michael Agger has criticized him for following a pattern of making "fragile, sealed-off movies that fall apart when exposed to outside logic."
The plot is simple. (Aren't all fairy tales? The enjoyment is in the details). Father Will Smith, in a bid to spend more time with his son (played by his son in real life, Jaden Smith), brings him on what should be a straightforward military mission. There is obvious love, but a lot of distance between (fictional) father and son, reflecting the very real-life issues that military parents have when they leave their kids at home for long and repeated tours of duty. The family is living on an alternate planet 1,000 years in the future, after Earth was made unfit by humanity's destruction of nature and a scourge of man-eating aliens plagues their new home planet, Nova Prime, but relationship issues between fathers and sons are still the same (of course they would be; no technological advances have yet made it easier for families to get along harmoniously, or for people to be able to communicate their inner lives well).
Following a crash landing that disables the mega-fighter/father, leaving just the two of them on a thousand-years-hence Earth (where everything has evolved to kill humans), son Kitai has to take a cross-country trek to find the tail of their spacecraft, retrieve the rescue beacon, and do it all on a timeline that's restricted by the need for him to suck down a special chemical so he can breathe in Earth's now-inhospitable air. Oh, and the mission that father and son were originally on? It was all about transporting one of those human-munching baddies that finds people by smelling their fear — and of course it is now on the loose.
Of course the entire scenario is fantastical, and of course, like any good story, the trials and tribulations Kitai has to go through are just window dressing to the central plot; the relationship between father and son, how to successfully deal with fear, the nature of fear itself, and how most of the time, we all have to learn lessons the hard way, no matter how well our parents have taught us to avoid those pitfalls. It's about how frustrating it is to be a parent and watch your child flailing, and how sometimes that could have serious consequences for your own life. It's about parents both teaching — and learning from — their kids. And how eventually most parents become dependent on their offspring, even though it is a difficult situation to address.
The whole story is a simple relationship parable, and that's why plausibility of the action isn't really very important, and the acting is. I found Will Smith to be, contrary to his usual slapstick-jokey persona in films (and IRL), so refreshing to see playing a buttoned-up man of gravitas and hidden pain. Smith's son, Jaden, is obviously a young actor, but absolutely held the movie together — he's in almost every scene — and has compelling, soulful eyes in a joker's face, just like his father. As a woman who will never be a father or a son, I came away from the movie feeling like I understood men just a little bit better, and I think that's a pretty significant achievement for a piece of art.
It's also a film with a heavily environmental message. Not only have we clearly poisoned ourselves and the planet leading to us all packing into giant spaceships and heading off to colonize space, but the Earth that father and son crash-land on is incredibly gorgeous — just like today's is — but now also life-threatening at almost every turn for the young Kitai. Long-shots of beautiful vistas with animals aplenty remind me of what I learned of America's bounty pre-European colonization, awash in buffalo and birds. The planet is now actively trying to off the poor kid, and it made me realize that even though we make a big deal out of bears, sharks, snakes and spiders, the Earth we live on now is Edenic in its safety. If the Earth actively evolved to get rid of us, I wouldn't be surprised; in this respect, the premise of "After Earth" was pretty believable.