“What’s the matter with him?” Steve asked. “He’s sick or something!” Sue cried out. She took the budgy from Steve and cuddled him in her own gloves. But the little blue bird seemed to be no better. Dr. Harding walked over to look at the bird. Then he ordered, “Everybody into the ore car! We have to get out of here fast! Sue, hold the bird up close to your suit!” The workers dropped their tools as if they were red hot and climbed into the car. Mr. Shannon helped Sue and Steve on, then jumped on himself. Dr. Harding pressed the electric button that was the signal to the operator in the main cavern to move the car. The car began to roll down the track. It picked up speed as Dr. Harding kept pressing the button. “Leaking gas, Dr. Harding?” Mr. Shannon asked worriedly. The chief engineer nodded. He sniffed the air like a hunting dog after a scent. “Take a deep breath, everyone, then hold it!” Steve thought his lungs would burst, but finally Dr. Harding let them take another deep breath. By the time they had taken one more, the car had reached the main cavern. As it rolled to a stop, Dr. Harding jumped down and ran over to the car operator. Steve saw a door slide down and close off the tunnel where they had come out. Then the little man gave a deep sigh and took off his black-rimmed glasses to wipe them. Sue and Steve watched Bud hopefully. He was standing more steadily on Sue’s finger now. “I think he’ll be all right,” the chief engineer said. “We sure owe Bud a lot for warning us the way he did. Something must have happened to the warning machine. It was supposed to set off a siren.” “If it weren’t for Bud we might have been overcome before we could have gotten out of there!” Mr. Shannon added. “You’re so right!” Dr. Harding said. “The men will go back in there in gas masks to find the leak and see what’s wrong with the warning machine.” “We’re plenty lucky!” Steve sighed, his spine still prickly from their narrow escape. Sue kissed the budgy. “You’re a hero, Bud,” she told him, “and we love you!” Bud blinked lazily. Then as if to show that he was all right again, he squawked, “Rocket away!” _THE BIG SHOW ON TITAN_ The space freighter had landed on Titan, the largest moon in all the Solar System. The Shannon twins had been anxious to reach this moon of Saturn because their father had told them that something very exciting might happen here before they left. There was still another reason why the children had looked forward to the landing. They would meet a boy of their own age who was the son of a worker. He had been living on Titan for the past two years and would be able to show them around. Steve and Sue came down the outside “gangway” of the cargo ship and stepped onto the frozen ground of the distant world. The twins wore space suits, of course, for the air outside was extremely cold and it was poisonous as well with raw methane and ammonia.