There is essentially only one character and the story starts in the middle.
In the year 2178 A.D. Helen Southcote is the only scientist left on the international space station when Earth is destroyed by an asteroid. With no hope of rescue, Helen has to come to terms with her situation.
Helen’s backstory unfurls; her family, relationships, colleagues and involvement with SETI – the search for extraterrestrial life.
Her main focus is the ‘Wow!’ message from the constellation of Sagittarius, recorded by Jerry Ehman in 1977. She works on SETI, searching for signs of intelligent life and sending her own radio messages towards Tau Sagittarii, the place where the Wow! message emanated from, 122 light-years away.
The events leading up to the destruction of Earth are dramatically depicted – the discovery of an asteroid, the political and social implications and the desperate measures taken to deal with the menace.
Alone on the space station, with only the ship’s computer, Eunice, for company, Helen considers her options and formulates a crazy plan.
She has Eunice fertilise the ova harvested from her body and cryogenically freezes her embryos.
Helen continues to send her radio messages through the 122 light-years of space, towards Tau Sagittarii. She takes the space station out of orbit around the shattered planet and begins a futile 150,000-year journey.
The last human being heads into the stars on a journey she will never complete.