Scientists thought that Earth was safe from invasion. But now an alien species --- from a planet hundreds of light-years from Earth --- is proving them wrong. A small spherical probe lands in an empty corner of New York City. It soon drills into the ground underneath, drawing electricity from the power lines to jump-start its automated expansion and prepare for alien colonization. When the government proves slow to react, NASA scientist Dr. Sarah Pooley realizes she must lead the effort to stop the probe before it becomes too powerful. Meanwhile, the first people who encounter the alien device are discovering just how insidious this interstellar intruder can be.