It’s really unnerving to contemplate the United States being invaded and occupied. It was unsettling when the original movie came out in 1984, and is just as unsettling now...even if the plot is a bit more unrealistic than it was in 1984.
North Korea has invaded the United States and taken over the West Coast and Midwest by using a new device that disables electronics and communications. Later we learn Russia has taken the East Coast at the same time. Jed Eckert (Hemsworth) and his brother escape the initial invading force parachuting in, along with a few others, and head for the woods to collect their bearing on what is happening.