The plane’s wheels touched down and the ship rolled along until a hook on it caught a line that stretched across the runway. The line brought the plane to a sharp halt.

The jet’s wings were folded down and the ship was pushed off to a hangar. Two more ships landed afterward. Then a blinding flash lighted up the sky. It made Steve and Sue blink and jump in fright.

“Look!” Bobby exclaimed. “The storm has begun!”

Other men had come out to see what was going to happen and they lined up along the edges of the skyport with the children.

Bobby pointed to a sparkling balloon of light that burst into a blossom of sparks over the mountains. A moment later a red dagger flash skipped across the peaks. During all this there were loud crashes and rumblings. Steve was scared and thrilled at the same time.

“It’s just like fireworks!” Sue called out.

Now Steve could understand why Bobby had looked forward to the storm. He guessed, too, that this was the exciting surprise their father had said might happen while they were here.

An orange pinwheel, like a Fourth of July sparkler, rose from a mountain top and looped upward. It grew bigger and bigger and fainter and fainter at the same time. It was really a beauty.

“What causes the fireworks?” Steve asked above the noise.

“Partly strong wind,” Bobby said loudly, “and partly Titan’s gases exploding against the mountain tops!”