River knows that one day they will leave. And everybody leaves, eventually. But they'll be leaving sooner that expected.
Simon will have another argument with the captain. "As long as you fly on my ship," Mal will say, blue eyes on fire and mad as Hell, "you'll live by my rules. You ever try a stunt like that again, Doctor, and I'll..."
"Perhaps we shouldn't be flying on your ship, Captain," Simon will say. Voice calm, mouth turned up at the edges. He'll be just as angry.
"Suit yourself," Mal will say, thinking that Simon is bluffing. He hasn't learned yet that Simon never bluffs.
So Simon will shrug his shoulders and return to their quarters to pack.
Zoe will try to talk him out of it, not even a half hour later. She'll try to tell him that not a lot of captains will be willing to take on a fugitive doctor and his crazy sister.
His crazy sister. River knows, and she tries, she tries so hard. But she can't always keep the inside from showing on the outside. Sometimes things get out, whether you want them to or not. Sometimes the blue is all that's left.
Jayne will say "good riddance," even though he's long past meaning it.
Book will say a prayer for their safe journey.
Kaylee will cry. River won't. Crying never helps anything, she learned that the hard way.
Kaylee will cry, and her lips will taste like salt when River kisses her. "I'm going to worry about you, so much, sweetie. So much, all the time. I wish you could stay."
"It wasn't forever," River will say. She won't be crying, because crying never helps. "It was never forever."