75 years ago, an alien fleet attacked Earth. Without warning. Without mercy. We were not prepared. Then the aliens abruptly left. We rebuilt. We armed ourselves. We swore: never again. The aliens never came back ... until now ... It's the year 2650. With overwhelming force the aliens have returned, striking deep into our territory, sending Earth into a panic. Our new ships burn like straw. All our careful preparations are wasted. Only one man, one crew, and the oldest starship in the fleet stand between the Earth and certain destruction: ISS Constitution.