It was Thursday morning, and D.W. had enjoyed the best sleep of her life. Opening her eyes, she saw that the happy dream wasn't over—her good friend Greta was still in the bed next to her.

She aroused the girl without hesitation. "Greta!" she whispered excitedly. "I had a wonderful dream. I dreamed I was a unicorn!"

"That's wonnerful, D.W.," mumbled Greta as she yawned and stretched.

"Only I wasn't a unicorn like you," D.W. went on. "I was a unicorn with hooves and everything. I ran around through the forest, and I ate grass, and sometimes I pooped in the grass."

Greta smiled. "You're such a funny girl," she gushed, rubbing D.W.'s hair with her knuckles. "You remind me of myself when I was forty."

Mrs. Read served the girls an early breakfast at the dining table. "I hate oatmeal," said D.W., poking at the mush with her spoon. "Don't you, Greta?"

"I love it," said the horse girl.

"Nobody's perfect," said D.W.

While Greta was shoveling oatmeal into her mouth, Pal scampered into the kitchen, yelping, and began to paw at her stockings. Glaring down at the little dog, she let out an unearthly howl, prompting Pal to flee in terror.

"Why'd you do that?" D.W. asked her.

"Did you hear what he called me?" was Greta's response.

"I hope you can make it to your school on time," Mrs. Read said to Greta while spooning more brown sugar on D.W.'s oatmeal.

"I've got plenty of time," Greta assured her. "I even have enough time to say goodbye to Fern."

"Are you leaving already?" said D.W. disappointedly.

"I have a life to go on with," said Greta with a tender smile. "But I'll see you again soon."

"How soon?" asked D.W.

"Sooner than you'd like." Greta giggled.

D.W. struggled to hold back her tears as Greta bid her farewell with a kiss on the forehead. Within minutes the horse girl was at the door of Fern's house, ready to say goodbye to another dear friend.

The two girls hugged long and tight. "I hope you'll visit more often, now that Mr. Baker's gone," said Fern.

"I will," said Greta. "I promise."

"Have a good trip home," said Fern as she waved the girl away.

Then she closed the door…and grinned sinisterly.

Greta walked six blocks in the direction of downtown Elwood City, apparently oblivious to the poodle girl dogging her steps. Fern concentrated hard, determined to stay on Greta's tail and keep willing herself invisible. This is so much more exciting than going to fifth grade, she thought, gripping the stone firmly. I hope I don't have to follow her all across town. If she lives so far away, why doesn't she ask her parents to drive her? Does she even live with her parents? Did she run away from them when she discovered her powers?

Greta went on four more blocks, then crossed the street and entered a lot where an old bank building had been demolished. Fern hurried after her, tiptoeing so that the girl wouldn't hear her footsteps. After glancing in all directions, Greta hid herself behind the rear wall. Don't tell me she lives here, thought Fern as she crept carefully through the tall yellow grass and fallen bricks.

Behind the ruined building she saw nothing but weeds and a few bags of smelly garbage. Greta was nowhere.

Fern stifled a gasp. All right, so she's gone. Don't panic. She could be hiding somewhere, or maybe…invisible.

Breathing shallowly, cautious not to bend the grass, she shuffled to and fro in search of a crack in the wall, a ladder to the ceiling, or some other route Greta might have used to escape. Just as she neared the plastic garbage bags, the ground seemed to dissolve under her feet.

In an instant she was falling through darkness. Before she had a chance to scream, her feet collided with soft ground, then her back.

Relieved that the fall had been short, but worried she might have soiled her dress, Fern pushed herself up with one arm and straightened her knees to stand. Looking up, she was amazed to observe that the sunlight had been completely blocked out. It's like a hidden cave with a swinging door, she thought. But where does it lead? Could other Brainchildren be hiding down here?

She walked silently toward the faint light that came from her left side; the soil was moist beneath her sneakers. She couldn't see where the cavernous corridor ended, nor could she make out Greta's image. If I don't keep up with her, I may get lost, she thought anxiously. Lengthening her stride, she quickly arrived at a bend in the passageway.

She rounded it, only to find herself face-to-face with Greta's back.

The horse girl turned and stared at her with an expression of shock and anger. It was then Fern realized that the dim light had been emanating from the golden spiral horn attached to Greta's forehead.

"Fern! You shouldn't be here! Get out, now!"

Oh, crud, Fern said to herself. I dropped the invisibility stone when I fell into the cave.

"How did you follow me without being seen?" asked Greta, her voice almost at panic pitch.

"So you are a unicorn," said Fern bravely. "Are there others like you?"

"I'm not answering any questions," said Greta, folding her arms. "Now go back the way you came, or you'll be sorry."

Fern lowered her eyes meekly. "Okay, Greta. It's better if I don't know your secrets."

She swiveled slowly and walked away from the outraged girl. Once around the corner, she looked back and saw that Greta was moving further into the cave, the yellow light from her horn illuminating the muddy walls.

Then she sprinted forward with all her strength. She passed Greta on the right side and kept going. "Fern, stop!" the horse girl cried after her.

This is stupid, thought Fern/Tegan as she hurtled through the corridor. I don't have any powers in this body, and God knows what I'll encounter at the end of this cave…

to be continued