“So what happens?”

Navarro shrugged. “I do not know, except this much: that somehow, at breeding time, they must pick up an extra charge of energy. Analyzing small animals, I have identified the compound which is formed to store this energy and release it, by gradually breaking down, as the organism grows. It is all used up at maturity. But where is the temperature necessary to build up this molecule? Only on Dayside.

“Now these gods are said to live, on Dayside and meet the Twonks of Twilight at the temple. You know the breeding ceremonies take place when libration has brought the temple into the sunlight.”

“Go on,” said Antella thoughtfully.

“Pues, one of the plants, has this life cycle; it grows in the Twilight Zone, on the sunward side, and its vines are phototropic. Eventually their growth and the libration bring them into the light. The spore-pods burst and the spores are scattered into the air. A few are blown back into Twilight, and they are now fertile; radiation has formed the necessary compound. Or consider one of the small insectoids I studied. It breeds here in the. usual manner, then the female crawls out into the light to lay her eggs. When they hatch, the little ones scurry back to the shade, and some of them reach shelter before they fry. Wasteful, of course, but even on this barren planet nature is a notorious spendthrift.”

“Wait a minute!” interrupted Kingsbury. Navarre liked to hear himself talk, but there are limits. “Are you implying that the Dayside gods are merely the sun? That because the Twonks have to have light when they breed, they’ve built up a sort of Apollo-cum-fertility cult?”