"Day after artifical day, outwitting the carnivorous saurians that had devoured their shipmates, the two survivors of the Heinlein exploratory mission to Artifact One picked their way through the vast, horizonless jungle that filled the hull of this star-traveling terrarium.
"They did what a man and woman struggling for survival usually do. They prayed for rescue. They searched for a way to escape. They fell in love.
"Then, from a rise in the forest, they saw a wall. And something on the wall saw them."
