Is a killer comet heading toward earth? As politicians-both on the left and the right-fight over what should be done about the potential worldwide disaster, scientists make a startling new discovery. The "comet" has just responded to a decades old message from the now-defunct Arecibo Observatory. Is the comet really an alien ship? And are these creatures the enemy, or potential allies against an even greater threat?

As the world waits breathlessly for the news from outer space, Julie Lopez just wants to forget her disastrous last day as a New Jersey cop-the day when she let down a fellow officer and he died. But fate won't allow her to retire to a quiet life as a chef. She and on-again off-again boyfriend Danny will end up playing a major role in the confrontation with the aliens.