All stars and habitable planets in the universe have vanished, leaving only those aboard space stations or starships. Civilization is crumbling.

Three oceans of human blood have been encountered, and a fourth appeared two weeks ago on the desolate moon AT-5.

In lieu of your death sentence you're exploring it in this rickety ship, the Iron Lung, using a map with coordinates of interest, a sonar system, a COI information terminal and a black-and-white snapshot camera.

You've reached the bottom.