Circling the Sun, under the caverns of Mercury, Expedition Sundiver prepares for the most momentous voyage in our history.

A journey into the boiling inferno of the sun, to seek our destiny in the cosmic order of life. For in a universe in which no species can reach sentience without being 'uplifted' by a patron race, it seems that only mankind has reached for the stars unaided. And now, the greatest mystery of all may be explained...