Evan let out a cry so loud, it made two kids fall off their chairs. Two other kids dropped their lunch trays.

His eyes bulged and his voice rose higher than the gym teacher’s whistle. “You—you—you—!” he sputtered, grabbing his throat.

Andy laughed. She pointed at his chair. “Evan, sit down. I was only joking.”

“Huh?”

“You heard me,” Andy said. “It was a joke. The Monster Blood is home, safe and sound.”

Evan let out a long sigh. He sank back into the chair. He didn’t care that he was sitting in the milk he had spilled.

“Annndrea,” he said unhappily, stretching out the word. “Annnndrea, that wasn’t funny.”

“Sure it was,” Andy insisted. “And don’t call me Andrea. You know I hate that name.”

“Andrea. Andrea. Andrea,” Evan repeated, paying her back for her mean joke. He narrowed his eyes at her sternly. “That new can of Monster Blood your parents sent you from Europe—it really is hidden away?”

Andy nodded. “On the top shelf of a closet in the basement. Way in the back,” she told him. “The can is shut tight. No way the stuff can get out.”

He stared hard at her, studying her face.

“Don’t look at me like that!” she cried. She balled up the sandwich tinfoil and tossed it at him. “I’m telling the truth. The Monster Blood is totally hidden away. You don’t have to worry about it.”

Evan relaxed. He pulled the Fruit Roll-Up from his lunch bag and started to unwrap it. “You owe me now,” he said softly.

“Excuse me?”

“You owe me for playing that stupid joke,” Evan said.

“Oh, yeah? What do I have to do?” Andy demanded.

“Come with me after school. To Kermit’s,” Evan said.

Andy made a disgusted face.

“Please,” Evan added.

“Okay,” she said. “Kermit isn’t that bad when I’m around.”

Evan held up the sticky Fruit Roll-Up. “Want this? I begged my mom not to buy the green ones!”

*  *  *

After school, Evan and Andy walked together to Kermit’s house. It was a gray day, threatening rain. The air felt heavy and wet, as humid as summer.

Evan led the way across the street. He started to cut through the backyards—but stopped. “Let’s go the front way,” he instructed. “Conan might be hanging out in back. Waiting for us.”

“Don’t say us,” Andy muttered. She shifted her backpack to the other shoulder. She scratched her arm. “Ow. Look at this.”

Evan lowered his eyes to the large red bump on Andy’s right arm. “What is that? A mosquito bite?”

Andy scratched it some more. “I guess so. It itches like crazy.”

“You’re not supposed to scratch it,” Evan told her.

“Thanks, Doc,” she replied sarcastically. She scratched it even harder to annoy him.

A few sprinkles of rain came down as they made their way up Kermit’s driveway. Evan opened the front door and stepped into the living room.

“Kermit—are you here?”

No reply.

A sour smell attacked Evan’s nostrils. He pressed his fingers over his nose. “Yuck. Do you smell that?”

Andy nodded, her face twisted in disgust. “I think it’s coming from the basement.”

“For sure,” Evan muttered. “Kermit must already be in his lab.”

“Kermit? Hey—Kermit, what are you doing down there?” Evan called out.

Holding their noses, they made their way quickly down the stairs. The basement was divided into two rooms. To the right stood the laundry room and furnace; to the left the rec room with Kermit’s lab set up along the back wall.

Evan hurried across the tiled floor into the lab. He spotted Kermit behind his lab table, several beakers of colored liquids in front of him. “Kermit—what’s that disgusting smell?” he demanded.

As Evan and Andy ran up to the lab table, Kermit poured a yellow liquid into a green liquid. “Uh-oh!” he cried, staring down at the bubbling mixture.

Behind his glasses, his eyes grew wide with horror.

“Run!” Kermit screamed. “Hurry! Get out! It’s going to BLOW!”

The liquid swirled and bubbled.

Kermit ducked under the lab table.

With a cry of horror, Evan spun round. Grabbed Andy’s hand. Started to pull her to the stairs.

But he had only taken a step when he stumbled over Dogface, Kermit’s huge sheepdog.

“Oof!” Evan felt the wind knocked out of him as he fell over the dog and landed facedown on the tile floor. He gasped. Struggled to choke in a mouthful of air.

The room tilted and swayed.

“It’s going to BLOW!” Kermit’s shrill warning rang in Evan’s ears.

He finally managed to take a deep breath. Raised himself to one knee. Turned back to the lab table.