In 2071 on a secret base on the moon, mathematician Jack Potter knows that his defaulting on his business deal with the alien Wheeler led to the mass destruction of the Earth.
Billions are dead.
The few survivors who escaped Earth via Wheeler's technology remain under attack by Wheeler. Internally, one of the members of the camp is sabotaging the earthlings' attempts to stay alive. When all of them seem doomed, the Gersham, another advanced alien race, arrives to offer Jack a new deal. Considering the calumnious results of his previous deal with an off-planet being, Jack has doubts as to whether to sign on with the Gersham. Then again, he has few options if the human race is to survive into the next century.