The team watched in horror as rocks started to batter the doctor. He managed to withstand them for a short while, then one large boulder caught him on the shoulder, forcing him to his knees. Another boulder struck a glancing blow to his head. As they watched, they saw Carson, unconscious and unprotected, being covered by rocks of varying sizes.

Then, suddenly, without any reason, the rocks stopped falling. It was as if a protective barrier had formed over the doctor. John looked at Rodney, hoping the scientist could come up with some sort of explanation for what had happened. However, the bewildered look on his face told John that Rodney was just as confused as he was.

It was Teyla who first realised something of what was going on. She was standing next to Ria and noticed a certain tension in the other woman's body. She reached her hand out to touch Ría's arm, and then drew her hand back quickly. It was almost as if Ria had a force field round her body.

"Colonel!" Teyla cried out.

John turned round and looked at Ria. She was concentrating ferociously as she stared at the doctor. John wasn't sure what she was doing, but he knew for certain that she was the one protecting Carson.

"Ronon!" John said, and then nodded towards Carson's buried body. The Satedan nodded in response and the two men ran forward towards the doctor. When they got there, John found it impossible not to look at eerie sight of rocks suspended in midair. There was no obvious reason for the rocks to just hang there. And for all John knew, it was just the strength of mind of a fragile looking woman that was keeping them there.

He and Ronon worked quickly to remove the rocks from on top of Carson. His body looked battered and bruised and bloody. His jacket had been ripped at the shoulder and blood was oozing out of the wound. There was another a bleeding wound on his head. And those were only the injuries they could see. It was impossible to tell just how badly injured he was, but John was also concerned about Ria, almost against his will. This strained look on her face, and the tension in her body had made him realise that whatever it was that she was doing, it was putting a lot of strain on her.

Between them, John and Ronon gently lifted the doctor away from the rocks. He moaned slightly as they moved him but didn't fully regained consciousness. They carried the doctor back to the others. As they laid him down on the ground, the doctor's eyes opened, a vivid blue.

"Take it easy, Doc," John said, but a gentle hand on his good shoulder. "You just had half a ton of rocks fall on you."

Carson looked up at him. The memory of what had happened could be seen in his eyes.

"But how . . . ?" He started to ask, then he caught sight of Ria. There was sweat running down her face and the veins in her neck were standing out with the strain. The doctor struggled to his feet, swaying slightly as he did so. John put out a steadying hand, and Rodney to call of his arm. Once Carson had got his balance, he walked the few paces to where Ria was standing. His face held an anxious expression as he looked down at the motionless woman be before him.

"I try to tell her you were all right," Teyla said. "But she would not listen, or could not."

Carson put a gentle hand to her face. "Ria, love," he said softly. "I'm okay. You can let go now, love."

Her eyes moved their focus from the rock fall to Carson's face. Her eyes looked deeply to his, as if she were looking into his soul. Once she was sure he was telling her the truth, it was as if a light went out, and her body sagged into the waiting arms of Ronon. Carson's first response was to reach out to her, his healing instincts to the fore. But his own battered body give out on him, and he too collapsed.

John's anxious eyes met Teyla's. She shook her head as uncertain about what had happened as he was.

"What the hell just happened?" Rodney's voice echoed John's thoughts.

"You're the one that claims to be a genius," John said. "But I don't know that even you can explain this one."

"Explanations can wait," Ronon said brusquely. "We need to get them back to Atlantis."

"For once, Mr Obvious is right," Rodney said. "Maybe once were there, we can come up with a rational explanation of what happened."

John intercepted a glance between Teyla and Ronon. He sensed they knew something, or suspected something, but there wasn't time to explore it at that moment.

"Ronon, are you okay with Ria?" The big man nodded.

"Rodney," John continued. "You help me it with Carson, and Teyla, keep an eye out for anything unusual."

The journey back to the Stargate was a tense one. With their double burden, it took them much longer than the outward journey. And John was also anxious about his two injured colleagues. Ria lay in Ronon's arms, as if dead. Only her shallow breathing told him otherwise. Carson slipped in and out of consciousness, moaning in pain from time to time. In addition to his more obvious injuries, John was concerned that there might also be internal ones. He knew that if that was the case, time was of the essence.

It was with a sense of relief that he greeted the site of the Stargate. Teyla ran forward and quickly dialled Atlantis and battered team stepped through the Gate on their way home.