Secret weapon

"What are you eating, Rodney?" asked Sheppard.

McKay glanced up, distracted momentarily from his meal. He waved a handful of something white in Sheppard's direction. "Marmite sandwiches," he mumbled around a mouthful of food.

"Yeah? Where the hell did you get those?" Sheppard put his MRE on the ground next to him and looked longingly at McKay's rations.

McKay smiled his smug grin. "I brought a couple of jars with me, and I thought I'd bring edible rations with me for a change." He looked across at Ford, who was chewing unsuccessfully on a lump of something that looked vaguely like meat.

Ford caught his glance and scowled back.

Sheppard shifted across the circle to sit next to McKay. He tried to sneak a look into McKay's ration packs. "Got any spares?" he asked hopefully.

"Of course not," McKay answered scornfully. "My supplies are precious. I wouldn't bring food that I wasn't going to eat."

"Oh go on, Rodney," Sheppard wheedled. "Just a bit. Please. I love Marmite."

Teyla watched the interchange, bemused. "What is this Marmite?" she enquired curiously.

Sheppard glanced across. "It's a kind of food," explained. "You eat it on bread. It's delicious."

Ford made a gagging noise. "You must be joking," he disagreed. "I think it's disgusting."

McKay gave up trying to guard his supply, and handed a sandwich over to Sheppard. He in his turn broke a piece off to offer Teyla.

Teyla took it curiously, sniffing at it. She pulled a face. "It does not smell very pleasant," she ventured.

"They say you love it or hate it," Ford commented.

Teyla cautiously took a nibble of the bread, then jumped up and rushed off to spit the bread into the bushes. She grabbed her water bottle and gulped down mouthfuls. Ford and Sheppard collapsed in helpless laughter, and even McKay couldn't help grinning at the Athosian's discomfort.

"And you eat that for pleasure?" she choked when she had recovered the ability to speak.

"It's very tasty and very nutritious," McKay answered through a mouthful.

Teyla shrugged and returned to her own food, watching as Sheppard and McKay tucked into the marmite sandwiches.

Teyla was just finishing her meal when she stood up suddenly, her water bottle falling unheeded to the floor. "Wraith!" she exclaimed hoarsely.

"Are you sure?" Even as he spoke Sheppard knew it was a stupid question. He was already on his feet, as was Ford. McKay was still bundling his equipment together as the other three stood round him in a tight circle facing outward, weapons at the ready.

Finally McKay was packed and the four moved into the nearby bushes to hide.

At first there was silence apart from the wind rustling in the trees. Then they heard the steady tramp of feet. The Wraith appeared at the edge of the clearing, looked around then headed across the clearing, directly towards the bushes where the team was hiding. They held their breath for a moment, then as it became obvious the Wraith would find them Sheppard fired a few rounds. As the Wraith staggered back the team started running. Just as it appeared they had escaped. McKay tripped over a tree root and landed heavily. As he lay for a moment, too winded to even call out, the Wraith caught up to him. By the time Sheppard realised McKay was no longer behind him he turned to see his colleague lying on the ground watching in terrified fascination as the Wraith reached out, ripped his shirt and placed his hand against the scientist's bare chest.

"Arrgh!" Sheppard steeled himself as the scream split the air – then realised that it was the Wraith, not McKay screaming. He ran back and helped McKay to his feet, and they watched in amazement as the Wraith staggered back holding his hand. He looked at them, his face twisted with pain and fear, then he collapsed to the ground.

"If looks could kill…" muttered Sheppard, as McKay struggled to catch his breath.

Teyla and Ford rejoined them and together the stared at the Wraith who lay unmoving.

"Is it a trick?" Ford asked.

"I have never seen them behave in such a way," Teyla responded. She gingerly nudged the Wraith with her foot.

"Are you okay?" Ford asked McKay.

"Yes, I think so," the scientist answered, looking shaken. "I don't know what happened."

"Maybe he didn't like your taste," Sheppard quipped.

McKay turned to pick up his pack, then turned back suddenly. "You don't think…" he said slowly.

Sheppard sighed. "We don't have time to discuss this right now," he urged. "Let's get away from here before his friends show up."

"No, wait," the scientist insisted. "I just want to try something."

"Shall I drag him, Sir?" offered Ford.

"No." Sheppard thought for a minute. If McKay had any idea how the Wraith had died it would be extremely useful. And if anyone could come up with the solution his money would be on McKay.

He watched, bemused, as the scientist opened his pack.

"Don't tell me you're hungry!" he exclaimed as McKay took out his last sandwich.

McKay looked up at him apologetically. "I know it sounds stupid, but Teyla… and she's… and it couldn't be that simple, but I have to find out."

Sheppard grunted impatiently. When McKay got an inspiration there was no stopping him, but he really did pick his moments.

McKay bent over the Wraith for a moment, then straightened again. "I guess it was a stupid idea," he mused, then suddenly bent down again. "But like all stupid ideas, it worked!" he cried exultantly.

Sheppard crouched down, eager to see what the scientist was so excited about. He looked blankly at the brown smear on the Wraith's face. "You rubbed marmite on him?" he asked blankly.

"Yes, but don't you see?" the scientist's excitement was palpable.

Sheppard looked closer, then whistled. Under the brown smear the Wraith's skin was bubbling and melting.

"That's why Teyla had such a strong reaction to it," explained McKay. "She has Wraith DNA in her. Major, do you realise what this means?" he continued triumphantly. "We found a way to kill the Wraith. Marmite!"