She nodded her head dumbly.
"You must bring in a great many plants, Hertha. Remember that—a great many. Don't forget that. When you go outside, through the locks, we lose air. Air is very precious, so you must bring in a great many plants."
"Yes, Jimmy."
"And you must plant them as I did."
"Yes, Jimmy."
He began to talk faster, in a race with the growing fever.
"I've gathered most of the oxygenating plants around the hut. So you may have to go into the forest to get enough."
"The—the forest?"
"You must, Hertha! You must!"
Her mouth twisted as if she were ready to cry. "For you. Yes, for you I will go into the forest."