midnight
Hume shoved Brodie into the back of his mind to center his thoughts on the various ways of delivering , to the waiting sportsman , a fair-sized alien feline . The lights in the bubbles went out one by one . Within the circle barrier of the force field men slept . And by midnight the rain began to fall , streaming down the sides of the bubbles , soaking the ashes of the fire . Out of the dark crept that which was not thought , not substance , but alien to the off-world men . But the barrier , meant to deter multi-footed creatures , with wings or no visible limbs at all , proved to be a better protection than its creators had hoped . There was no penetration -- only a baffled butting of one force against another .