Yes it's the latest flick from Mr. Night Shyamalal's kitty, the guy is back to spook you, but this time around it's a warning...the movie covered with a evident layer of "save your planet" warnings, portrays a bizarre account of "organic" attack, which evidently is killing people in North-East Coast of America. Apart from the director's warning message, I would give you a warning too, the movie is full of disturbing dead bodies lying about on roads. People just die in the movie, for obvious reasons off-course, it's something scientific. There is an imbalance between the beings and the plants and they are on a spree of exuding some toxic chemicals that instigate in those affected a strong urge to kill themselves, spontaneously.
Mark Walbherg, the destined hero, survives out of his many membered team, his wife apparently cheating on him, confesses to her husband the truth in case they all were to die. The catastrophic event does leave many survivors. But the logic remains as one of nature's mysteries that no-one can unearth.
As to the probability of such an event occurring in real life cannot be doubted, Obviously on not that big a scale, but the man-nature equation once affected can reap harmful consequences. The movie even portrays the much speculated chemical attack that seems to be the next terrorist threat. The event is initially believed to be an act of terrorism, but it's later given off to the plants. It's a freaky movie, the director does manage to scare his audience at one point or another.