Natasha, who was brought up in an orphanage in Hiroshima, Japan, until the age of twenty, has always wondered who her parents were. She is one of the two female commanders based on a space lab, the other being Maria Francis. They have been tracking two large asteroids that are due to pass by the earth in a few months. Tinned food, mobile phones, and other everyday objects are found on the seabed--not unusual, except that they are over 250,000 years old. The asteroids change direction and are now heading directly for earth. A third asteroid becomes visible; this appears to be metallic in composition. An archaeological dig in Egypt finds a modern pair of spectacles in a sealed organ jar, and a modern digital watch turns up in a Japanese museum. Both items are over 250,000 years old. "What's going on?" asks General Payton.