With discovery imminent, the aliens reveal themselves by sending a videotape to the news media. This date becomes known as The Day Everything Changed. On the tape, an alien announces that it is an ambassador from the Traders, who wish to colonize Mars. Although individual Traders aren't as intelligent as humans, over millions of years they have slowly built an advanced technology that they propose trading for commodities and human intellectual creativity. They initially offer a device that uses hydrogen fusion to produce electric power, which crashes the energy markets.

Humans display a wide range of reactions to the Traders. A company is set up to supervise the distribution of Trader technology, collect royalties for its use, and reduce the corruption that the Traders see as a great obstacle to human progress. This organization encounters industrial spies and rogue governments trying to subvert its mission. Traders fear humans will surpass their technology, so they try to withhold their ultimate secret.