Her whole head began to itch as she imagined what it must feel like to have leaves uncurling from your scalp.

A crow flew low overhead, cawing loudly. Margaret raised her eyes to follow the bird, but the sight of the hideous leaves sprouting from her father's head wouldn't go away.

"It's okay. Really," Dr. Brewer repeated, hurrying over to them.

"Your head -- it's all green!" Casey repeated.

"But, Dad -- your head," Casey stammered. He suddenly looked very pale.

Margaret felt sick. She kept swallowing hard, trying to ride out the waves of nausea.

"Come here, you two," their father said softly, putting an arm around each of their shoulders. "Let's sit down in the shade over there and have a talk. I spoke to your mom on the phone this morning. She told me you're upset about my work."

"Kids -- it's okay!" Dr. Brewer called. He bent down quickly, picked up the baseball cap, and replaced it on his head.

"I know," Dr. Brewer said, smiling. "That's why I put on the cap. I didn't want you two to worry."

He led them to the shade of the tall hedges that ran along the garage, and they sat down on the grass. "I guess you two think your dad has gotten pretty weird, huh?"

"It's a side effect," he told her, continuing to hold her hand. "It's only temporary. It'll go away soon and my hair will grow back."

"Margaret, you haven't said a word," her father said, squeezing her hand tenderly between his. "What's wrong? What do you want to say to me?"

He stared into Margaret's eyes. Feeling uncomfortable, she looked away.

Cawing frantically, the crow flew over again, heading in the other direction.

Margaret sighed and still avoided her father's glance. "Come on. Tell us. Why do you have leaves growing out of your head?" she asked bluntly.

"You haven't had any time," Margaret corrected him.

"Maybe you two would feel better if I explained what I'm trying to do down in the basement," Dr. Brewer said, shifting his weight and leaning back on his hands. "I've been so wrapped up in my experiments, I haven't had much time to talk to you."

"But how did it happen?" Casey asked, staring at his father's Dodgers cap. A few green leaves poked out from under the brim.

"I'm sorry," he said, lowering his eyes. "I really am. But this work I'm doing is so exciting and so difficult."

"Did you discover a new kind of plant?" Casey asked, crossing his legs beneath him.

"Have you ever talked about DNA in school?" their father asked. They shook their heads. "Well, it's pretty complicated," he continued. Dr. Brewer thought for a moment. "Let me try and put it in simple terms," he said, fiddling with the bandage around his hand. "Let's say we took a person who had a very high IQ. You know. Real brain power."

"No, I'm trying to build a new kind of plant," Dr. Brewer explained.

"Huh?" Casey exclaimed.

"Like me," Casey interrupted.

"Casey, shut up," Margaret said edgily.

"A real brain. Like Casey," Dr. Brewer said agreeably. "And let's say we were able to isolate the molecule or gene or tiny part of a gene that enabled the person to have such high intelligence. And then let's say we were able to transmit it into other brains. And then this brain power could be passed along from generation to generation. And lots of people would have a high IQ. Do you understand?" He looked first at Casey, then at Margaret.

"Not exactly," their father said, lowering his voice. "I'm doing something a little more unusual. I really don't want to go into detail now. But I'll tell you that what I'm trying to do is build a kind of plant that has never existed and could never exist. I'm trying to build a plant that's part animal."

"Yeah. Kind of," Margaret said. "You take a good quality from one person and put it into other people. And then they have the good quality, too, and they pass it on to their children, and on and on."

"Very good," Dr. Brewer said, smiling for the first time in weeks. "That's what a lot of botanists do with plants. They try to take the fruit-bearing building block from one plant and put it into another. Create a new plant that will bear five times as much fruit, or five times as much grain, or vegetables."

"And that's what you're doing?" Casey asked.

Casey and Margaret stared at their father in surprise. Margaret was the first to speak. "You mean you're taking cells from an animal and putting them into a plant?"

"How do you do it?" Margaret asked, thinking hard about everything he had just told them. "How do you get these cells from the animals to the plant?"

"I'm trying to do it by breaking them down electronically," he answered. "I have two glass booths connected by a powerful electron generator. You may have seen them when you were snooping around down there." He made a sour face.

"Yeah. They look like phone booths," Casey said.

"One booth is a sender, and one is a receiver," he explained. "I'm trying to send the right DNA, the right building blocks, from one booth to the other. It's very delicate work."

"I've come very close," Dr. Brewer said, a pleased smile crossing his face. The smile lasted only a few seconds. Then, his expression thoughtful, he abruptly climbed to his feet. "Got to get back to work," he said quietly. "See you two later." He started walking across the lawn, taking long strides.

He nodded. "I really don't want to say more. You two understand why this must be kept secret." He turned his eyes on Margaret, then Casey, studying their reactions.

"And have you done it?" Margaret asked.

But, as Margaret made her way into the house, she found herself troubled by what her dad had said. And even more troubled by what he hadn't said.

Dr. Brewer shrugged. "Nothing to explain," he said curtly. "Just a side effect." He adjusted his Dodgers cap. "Don't worry about it. It's only temporary. Just a side effect." Then he hurried into the house.

"But, Dad," Margaret called after him. She and Casey climbed to their feet, too. "Your head. The leaves. You didn't explain it," she said as she and her brother hurried to catch up to him.

Casey seemed really pleased by their dad's explanation of what was going on in the basement. "Dad's doing really important work," he said, with unusual seriousness.

A side effect from what? What actually caused it? What made his hair fall out? When will his hair grow back?

Margaret closed the door to her room and lay down on the bed to think about things. Her father hadn't really explained the leaves growing on his head. "Just a side effect" didn't explain much at all.

It was obvious that he hadn't wanted to discuss it with them. He had certainly hurried back to his basement after telling them it was just a side effect.

There were lots of other questions Casey and I should have asked, she decided. Like, why were the plants moaning down there? Why did some of them sound like they were breathing? Why did that plant grab Casey? What animal was Dad using?

Not to mention the one Margaret wanted to ask most of all: Why were you gulping down that disgusting plant food?

Yuck. Thinking about it made her itch all over. She knew she'd have hideous dreams tonight.

It made Margaret feel sick every time she thought about it.

His explanation was really interesting, as far as it went, Margaret decided. And it was good to know that he was close to doing something truly amazing, something that would make him really famous.

She grabbed her pillow and hugged it over her stomach, wrapping her arms tightly around it.

What must it feel like? Green leaves pushing up from your pores, uncurling against your head.

But she couldn't ask that one. She couldn't let her dad know she'd been spying on him.

Lots of questions.

A side effect.

She and Casey hadn't really asked any of the questions they'd wanted answered. They were just so pleased that their father had decided to sit down and talk with them, even for a few minutes.

Otherwise, it will drive me crazy. I'll think about it and think about it and think about it. Every time I see him, I'll picture him standing over the sink, shoving handful after handful into his mouth.

I've got to ask him about the plant food.

She was still thinking about all of these questions late that night -- after dinner, after talking to Diane on the phone for an hour, after homework, after watching a little TV, after going to bed. And she was still puzzling over them.

I've got to ask him, she decided.

Glancing at the clock, she saw that it was two-thirty in the morning.

But what about the rest of it?

No, she quickly decided. No. Dad wouldn't lie to us.

There are just some questions he hasn't answered yet.

A frightening thought entered her mind: Could he have been lying to them?

But she realized she was wide awake.

When she heard her father's soft footsteps coming up the carpeted stairs, she sat up in bed. A soft breeze fluttered the curtains across the room. She listened to her father's footsteps pass her room, heard him go into the bathroom, heard the water begin to run into the sink.

The hand was still bleeding, Margaret saw.

He didn't notice her. He was concentrating on the bandage on his hand. Using a small scissors, he cut the bandage, then pulled it off.

He was standing at the sink, leaning over it, his chest bare, his shirt tossed behind him on the floor. He had put the baseball cap on the closed toilet lid, and the leaves covering his head shone brightly under the bathroom light.

Margaret held her breath.

And I have to know it.

What was that dripping from the cut on her father's hand?

I'll just ask him point-blank.

She stepped into the narrow triangle of light and peered into the bathroom.

The leaves were so geeen, so thick.

She heard him cough, then heard him adjust the water.

She padded softly down the hall, a sliver of light escaping through the bathroom door, which was slightly ajar. Water still ran into the sink.

Or was it?

I have to know the answer, she thought.

There's got to be a simple explanation, she told herself, climbing out of bed. There's got to be a logical explanation.

"Who's there?" Dr. Brewer cried. "Margaret? Casey?"

He saw me -- and now he's coming after me.

It couldn't be blood -- could it?

It couldn't be blood dripping into the sink.

It was bright green!

Margaret stared hard, trying to better focus her eyes.

After washing, the cut continued to bleed.

He poked his head into the hallway as Margaret disappeared back into her room.

She gasped and started to run back to her room. The floor creaked under her footsteps.

Still holding her breath, she watched him wash it off carefully under the hot water. Then he examined it, his eyes narrowed in concentration.

He saw me, she realized, leaping into bed.