Disclaimer: I don't own the Star Wars characters. I just made up the plot, and Umber.
Jacen stood by the Falcon, thinking. When he had left Luke's office, he had come out here to think. Jaina would have made the decision he was pondering instantly, but he was thinking it through.
Once, when the twins were about ten years old and living on Coruscant, too young for the Luke's Jedi training, Han had to make a run in the Millennium Falcon. He was going to deliver a load of supplies to Luke's academy on Yavin 4. When Jaina asked to come, Han had told her that she couldn't go and that was final.
But Jaina wouldn't take no for an answer. Telling only Jacen, she had sneaked aboard and hidden in one of Han's smuggling compartments. When they got to Yavin 4 and Luke and Han were unloading the ship, Luke had found her and she had gotten in big trouble with first Luke, then Han, then Leia.
Still, the point was that it had worked. She had gone to Yavin 4 despite the fact that Han had refused to take her.
Jacen thought that if he could get to the Imperial hideout without being detected, he could slip off and find Jaina. Then his parents and his uncle would be so glad that Jaina was safe that they would forgo any punishment for Jacen disobeying.
On the other hand, when did anything go exactly as planned? If he was caught, he would be in trouble and worst, Uncle Luke wouldn't trust him anymore. It was bad enough having his parents be mad, but when Uncle Luke looked at him sorrowfully and said, 'I thought I could trust you, Jacen,' that was the worst.
But Jaina would do it. She would go save him if he were the one kidnapped by Imperials. She wouldn't be scared, or have second thoughts. What would she say to him now if he could hear her? He knew. 'What are we waiting for?' He had to do this. Uncle Luke and Mom and Dad could say what they wanted, but Jacen was going to do the right thing.
He slipped onto the ship and thankfully found it empty. He pried one of the floor tiles up, and found the space beneath it empty. He lowered himself inside and pulled the tile back over the yawning hole.
Inside the compartment, it was dark, musty, and cold. Obviously hasn't been used since Jaina's trip. He imagined a younger Jaina curled up in one of the corners, hoping in vain not to be found. He shivered and wondered if it got any colder during the actual flight. Probably.
Footsteps.
"Did you say goodbye to Jacen?" Leia's voice.
"No," Han answered. "Haven't seen him since we told him he had to stay here."
"It's better for him," Leia said.
Chewie bellowed his agreement.
"Maybe," Luke's voice cut in. "But maybe you have to let him grow up a little."
Han snorted. "Listen, kid. You have children, you can decide for them. But Jacen's our son."
"I understand," Luke responded. "I won't argue about it. He's a good kid, and he knows how to follow directions."
Uncle Luke knows! Jacen thought. But then he rethought it. If Luke really knew, he would tell Leia and Han. He trusted their judgement. But he should have sensed Jacen by now. He was, after all, a Jedi. But the blanket that had been dropped over Jacen may be cutting off not only his ability to sense Jaina and other people, but other Jedi's ability to sense him. That made sense.
"I'm going to get the ship started," Han was saying. His and Chewie's footsteps trailed away.
"Oh my," came the prissy voice of Threepio. "Another trip on a starship going to fight Imperials. I tell you, Artoo, this time we're doomed for sure."
Artoo made a rude noise.
"Well, I say, that was uncalled for."
"Watch your language, Artoo," Luke admonished. "And Threepio, calm down. We are not doomed. Why don't you two go run the pre-req. tests? Han usually doesn't bother with them and he should."
"Why, certainly, Master Luke. Come along, Artoo."
Artoo grumbled, but complied. Jacen could hear Threepio's footsteps clanking, and Artoo's wheels squeaking as they left.
"Luke, do you think she's okay? Really?" Leia was asking.
"I hope so, but you know Jaina's tendency to talk back for what she believes in. That could get her into trouble," Luke answered.
"She does talk back a bit. Han hates it when she does that, but she's just like him. He doesn't want to believe he can be that annoying sometimes."
"Buckle up!" Han yelled from the cockpit. "We're leaving this joint!"
Jacen braced himself against the wall. It was going to be a long ride.