This is my first short and one-shot ever, so bear with me. This is one of my theories as to how Jack will find out about Claire's connection to him. And please don't ask how things got the way they are, they just did.
And this was written before episode 4x09, so any mistakes aren't intended.
Disclaimer: I own nothing, this is only a theory and written for the enjoyment of anyone who wishes to read this. I however am not making any profit from this piece of written work.
"So they're sending the helicopter back to pick up the rest of us?" Jack asked, talking into the phone, as he walked alone through the jungle and came upon a small clearing.
"Precisely." Sayid's voice came from the other end, as he replied from the freighter. "We'll all be home before you know it."
"Well most of us anyway." Jack said referring to Locke's group. "So when will you come for us?"
"Just give us the word and we'll start off." Sayid said.
"I'll clear it with the group and then I'll tell you." Jack said.
"I'm afraid I can't let you do that Jack." a voice suddenly came.
Jack whipped around as John Locke came into the small clearing from the jungle foliage.
"Jack? Is that John?" Sayid's voice asked.
"Yeah it is." Jack said bitterly.
"Jack, this is your last chance, let me help you. Let me help everyone, that's all I've ever wanted to do. You have to have seen by now what these people are like." John said.
"The only thing I've seen is a crazy old man, who was on a plane crash and will stop at nothing to stop everyone else from getting off this god forsaken spit of land! And will resort to even killing innocent people like Naomi and Boone, for his own doing! Do you honestly think that I'm going to listen to you?" Jack yelled at John.
John sighed.
"Jack I'm going to give you to the count of 5 to hand me that phone." John said.
"Don't do it Jack." Sayid's voice said.
"1." John said calmly.
"John." Jack said.
"2." John said continued.
"No." Jack said.
"3." John said getting a little agitated.
"No, John." Jack said raising his voice.
"4." John said warningly.
"You're crazy!" Jack said more intense.
"5." John said in an irritated voice.
"I'm not going to give it to you!" Jack shouted.
John sighed then said simply, "I hoped it wouldn't have to come to this. I'm going to have to take it from you by force."
"Oh really?" Jack said unimpressed, "You and what army?"
Suddenly, out from the trees into the clearing, all armed with guns, stepped Sawyer, Miles and Ben.
"That army Jack." John said.
"Jack, what's going on?" Sayid's voice asked.
"I-" Jack said.
"Give us the phone Jack." John said.
"You think I'm going to give it to your group, when they're letting him walk around, with a gun?" Jack said motioning to Ben.
"Well doc, that ain't exactly a group decision." Sawyer said.
"Jack, what's going on?" Sayid asked.
"Don't tell him Jack." Ben said. "It's not worth it."
"What's going on with them?" Desmond's voice asked Sayid in the background.
"I don't know." Sayid's voice replied.
Miles stood the closest to Jack. He was doing this against his will. It was either do it or die, and he still hadn't gotten what he wanted, so dying wasn't exactly an option.
"Jack." Miles whispered. "The code."
"What?" Jack whispered back.
"Remember, Sayid was there when I told you the code, he'll understand." Miles whispered back.
"What code?" Jack whispered.
"The one Naomi used when she died." Miles whispered back.
Then Jack remembered.
"It's nothing Sayid, just John, Sawyer, Miles and Ben is here." Jack said.
"That's nothing?" Sayid asked unbelieving.
"Yeah." Then Jack paused. Then he said, "Tell my sister I love her."
"Jack what are you- Oh." Sayid's understanding voice came.
Jack and Miles looked at each other, and the latter slightly nodded.
John and Sawyer looked at each confused.
"What the hell does that mean doc?" Sawyer asked confused.
Jack just smiled and said, "You got that Sayid; tell my sister I love her."
"If you hand the phone to John you can tell her yourself." Ben said.
"What?" John and Sawyer asked.
"What?" Sayid, Desmond and Miles repeated.
"What?" Jack asked confused.
"If you give the phone to John, you can tell your sister that you love her yourself." Ben said.
"I don't have a sister." Jack said.
"Then why'd you ask to tell your sister you love her if you don't have one?" Sawyer asked.
"It's code for 'I've got a gun to my head'." Miles said.
"He's right, but I don't have a sister." Jack said firmly.
"Actually you do have a sister, well a half-sister anyway." Ben said offhandedly, "Actually she's on the island, right now."
By now Jack knew that Ben probably wasn't lying because Ben did retain vast amounts of information about everyone on the island.
"Who's my sister?" Jack asked.
"Oh it's Claire." Ben said.
Everyone was silent.
"Oh, did you not know that?" Ben asked.