An international naval coalition becomes the world's last hope for survival as they engage a hostile alien force of unimaginable strength called The Regents who attempt to invade Earth to build a power source in the ocean. Lieutenant Alex Hopper (Taylor Kitsch) is assigned to the ship USS John and winds up commanding the team responsible for repelling the invaders before it's too late. In the daunting mission, Hopper must also try to live up to the potential his brother Stone (Alexander Skarsgård) and his fiancée's father, Admiral Shane (Liam Neeson), expect of him.