When Arthur, D.W., and Francine arrived in front of Lakewood Elementary the next day, Fern approached them immediately, ready to burst with the good news.

"Hey, guys!" she called out. "Guess who's coming to my house tonight!"

"Frank Gehry?" guessed Francine.

"Koko Taylor?" guessed Arthur.

"Jack Prelutsky?" guessed D.W.

"None of the above," said Fern excitedly. "It's my friend, Greta von Horstein."

Arthur, Francine, and D.W. froze in their tracks. The school's metal door swung back and hit Arthur's rear end.

"What's wrong?" asked Fern when she saw the stunned looks on their faces.

"Uh, nothing," said Arthur, forcing a smile.

"Yeah, we'd love to see Greta again," said Francine insincerely.

"Greta! Greta! Greta!" gushed D.W., jumping and waving her hands.

"She'll be there at six," Fern told them. "You're all welcome to come."

"Awesome!" cried D.W. as she rushed forward to embrace the poodle girl around the legs.

"Why are you hugging me?" Fern asked.

"I like to hug the bringer of good news," replied D.W.

Fern patted the little girl on the head and skipped away, leaving Arthur and Francine to face each other grimly. "If Greta's back, that can only mean trouble," Francine remarked.

"You don't need to tell me that," said Arthur.

"The last time we saw her," Francine recalled, "she tried to force us to leave our families and join her in the underground world of the unicorns."

"Yeah," said Arthur, "but you don't need to tell me that."

"And before that," Francine went on, "she turned D.W. into a unicorn, and we had to go through all kinds of trouble to get her changed back."

"Francine," said Arthur, "you don't need to tell me that."

"I'll ask her to turn me back into a unicorn," said D.W., clasping her hands and gazing wistfully into the air. "Then I'll live underground with her, and never have to go to another piano lesson with Dr. Fugue."

"On the other hand," said Arthur, ignoring her, "she did save our butts when the X-Pets tried to kill us and destroy the city."

"Yeah, you're right," said Francine thoughtfully. "And without her magical horn, Marina would've never been cured of amnesia. I guess we should give her another chance to be our friend."

"Are you kidding?" D.W. scolded them. "Of course you want Greta to be your friend. Unicorns are so cool, you should consider yourself lucky if you have one as an enemy."

"Fine," said Arthur. "We'll go to Fern's and see her. Now go to class, D.W."

His little sister bounded away, muttering "Greta's coming! Greta's coming!" with delight.

She entered Mrs. Frensky's first-grade classroom, where her friends Nadine, Tommy, Timmy, Emily, Vicita, Dallin, and James were preparing for the beginning of class by making as much noise as possible.

"Why so happy, D.W.?" said Mrs. Frensky when she saw the smiling aardvark girl walk in.

"I get to see my friend Greta after school," D.W. told her.

"But don't you have a piano lesson after school?" said the teacher.

D.W.'s smile dropped into a frown. "You had to ruin the moment, didn't you?" she grumbled, trudging toward her desk.

During first period the children practiced their cursive writing. D.W. paused in the middle of her exercise to ponder her options. I don't think the unicorn idea's gonna fly, she thought. I need to think of some other way to get out of piano lessons with Dr. Fugue.

I could run away, but I'd probably get hungry after a month.

I could shoot Dr. Fugue in the eye with a rubber band. No, he's prepared for that—he wears glasses.

Sue Ellen's an alien. I could ask her to abduct me.

I could pick a fight with Rattles and get sent to the hospital, where they'd give me candy and ice cream. No, wait—that would hurt a lot.

I could pick a fight with somebody my own size, and go to the principal's office, and get detention.

I could dye my hair and put on a fake moustache, and call myself Ida P. Morgenstern.

I could join the army, like Francine's sister did, and get sent to Karjakistan.

I could stand in the middle of the street and…wait, what was that idea about detention?

She looked over at the adjacent desk, where Nadine was busily etching cursive letters. How can I do this to my best friend? she thought. But no one else would understand. It has to be her.

She swallowed, anxious that her stratagem might cost her a valuable friendship.

"Hey, Nadine," she whispered.

The squirrel girl turned her head and smiled.

D.W. pointed to a spot on Nadine's sheet of paper. "That w looks like somebody's butt," she said mockingly.

"Does not," Nadine retorted.

"Does too," D.W. insisted. "It looks like Dallin's butt." Her voice grew in volume. "You drew Dallin's butt. You're in love with Dallin!"

"Shut up!" exclaimed Nadine as Dallin glanced at her and blushed.

"Girls, be quiet, please," said Mrs. Frensky.

"She started it!" Nadine complained.

"That's enough, Nadine," said the teacher sternly. "Don't make me send a note to your mother."

D.W. was about to open her mouth again, when…a note to her mother?

"Sorry, Mrs. Frensky," said Nadine meekly.

A note to her mother? thought D.W. bitterly. What kind of punishment is that? If I want detention, I'll have to do something more heinous.

But what? With cursive practice occupying her mind, how would she think of an idea?

As the kids filed out at the end of first period, Nadine confronted her friend. "You're mean, D.W.," she grumbled. "I'm not in love with Dallin, and I didn't draw his butt."

"Shh, Nadine," said D.W. mischievously. When she was certain that all the other students had left and Mrs. Frensky wasn't paying attention, she whispered, "I'm trying to get detention so I can skip my piano lesson with Dr. Fugue."

Nadine's scowling lips curled into a wicked smile.

"It's hard for a first-grader to get detention," she explained to D.W. while walking past the playground during morning recess. "You basically have to endanger someone's life."

"I've got to do something," said D.W. with a shrug, "or Dr. Fugue will endanger my life."

"What about Arthur?" said Nadine. "You hate him, don't you?"

"No, I just find him annoying. I don't really hate anybody at the school—except maybe Rattles."

"Well, there you go," said Nadine with a satisfied grin. "Throw a rock at him or something."

"He'll kill me," said D.W.

"Wait a minute," said Nadine, stopping and bending over.

She whispered something into D.W.'s ear, and the aardvark girl's eyes brightened. "That's a great idea!" she exclaimed.

to be continued