I Am Number Four(2011)

John (Alex Pettyfer) is apparently a normal teenager who goes to school like his peers. But John is not an ordinary teenager, but an alien who escaped from a planet called "Magador" and took refuge on Earth. In fact, he is the fourth of the nine people (so-called Magadorians) who left this planet and came to earth; The previous 3 Magadorians have been killed, and now John is the only one who needs to be eliminated, and the Magadorians are planning to come to Earth to destroy him...