Project Almanac first trailer.
The Butterfly Effect is examined writ large in this new SF time travel found-footage flick in which a group of friends discover plans to build a time machine and then build one themselves.
They use their time device initially to undo past mistakes, but eventually their goals turn towards their own gain and pleasure – and they soon realize that changing the past has dire consequences in the future when people start vanishing and events are changed . . . TERRIBLY!