Confirmation of extraterrestrial life appears on television screens across the world as a massive spacecraft breaks through the atmosphere on a crash course into the Atlantic Ocean. A young paramedic, Greg Baker, signs up to fight for his planet against the invaders. Baker joins Special Forces members as the squad medic as they escort a classified package by chopper over enemy territory. When their chopper is shot down they find themselves surrounded and outnumbered. Desperate to return to his wife's side and haunted by nightmares, Baker find that his role in the war has quickly become much larger than he could have ever imagined. The mysterious package may be the key to turning the tide of the war, and possibly to saving all of humanity, but Baker must decide whether to protect it or sacrifice it to ensure his own survival.
A parasitic alien soul is injected into the body of Melanie Stryder. Instead of carrying out her race's mission of taking over the Earth, "Wanda" (as she comes to be called) forms a bond with her host and sets out to aid other free humans.
Jack Harper (Tom Cruise) is one of the last few drone repairmen stationed on Earth. Part of a massive operation to extract vital resources after decades of war with a terrifying threat known as the Scavs, Jack’s mission is nearly complete.
Iconoclastic, take-no-prisoners cop John McClane, finds himself for the first time on foreign soil after traveling to Moscow to help his wayward son Jack - unaware that Jack is really a highly-trained CIA operative out to stop a nuclear weapons heist.
When the crew of the Enterprise is called back home, they find an unstoppable force of terror from within their own organization has detonated the fleet and everything it stands for, leaving our world in a state of crisis.