Sentience

True-Humans —

They thought themselves he lords of the universe and looked upon D'Neerans, the only human telepaths, as being not quite human, not quite trustworthy. But a few true-humans could see the promise and the possibilities of the D'Neerans. So when Jameson, true-human master of manipulation launched the exploratory starship Endeavor, one D'Neeran, the Lady Hanna, a navigator and telepath who had studied the known sentient races was part of the crew.

The Endeavor began its star search, broadcasting a message of greeting and hope. But when an answer finally came, it was meant for the single D'Neeran aboard - and upon her would rest the fate of all humankind.