Ok, so James Franco is trying to find a cure for Alzheimer's disease and testing his medicine on monkeys, it works but he gets the sack and ends up keeping a super intelligent baby monkey in his attic, already we're like, what? How can he afford to do that and why does no one find out for like five years? He cures his declining father with the same formula but after a few years John Lithgow's immune system gets rid of the stuff and Franco sets to work making a better version of the magic potion.
Franco's super-monkey hurts the unlucky guy who lives next door through protecting Lithgow (as monkeys do) and he gets put into an EVIL monkey sanctuary that literally would not exist in reality. The guys who work there are dicks and you wonder if they hate monkeys so much why do they work at a monkey sanctuary? "I like violence and I hate animals." "We have the perfect job for you, at the monkey sanctuary!"
Back at the pharmaceutical company Franco used to work at before getting fired at the start the greedy British black man who owns it gives him the go-ahead and they all decide to try the new medicine on the most EVIL looking monkey they can find... British black man then watches new improved evil clever monkey drawing evil bananas and writing his name on a list under the heading of 'To Kill' but is not worried at all.
Main monkey becomes king and somehow the other monkeys understand what he asks them to do despite the fact they are just monkeys (???) he makes them intelligent however with new improved gas- which coincidentally is deadly to humans. Unlucky guy next door catches a face full of deadly germs and it is revealed over the end credits (after all the intelligent monkeys have run into the woods and turned over a load of cars etc.) that he is a pilot and he spreads the plague all over the work thus eradicating the human race leaving apes as the ruling species. The End.
I really enjoyed Tom 'Draco Malfoy' Felton, playing the biggest douchebag of all time, how awesome to deliver the line, "Get your stinking paw off me, you damn dirty ape!" He was really good and his American accent was far better than Dominic Cooper's in Captain America.