I Am Number Four follows the Twilight series’ playbook in casting a high school outsider as an otherworldly character. In this case, he’s an alien from outer space who changes schools the way normal kids change T-shirts because other aliens are out to destroy him. The movie is a mixed bag, with many of the elements fun and intriguing, but since this is also a Michael Bay-produced movie, CG monsters and cartoon bad guys gum up a third act that cries out for a more sophisticated climax rather than another tedious battle royal taking place mostly in the digital realm.