Declan led us through a heavy door and down a long corridor. He ushered us into a small room with a table and three chairs around it.

“Wait here,” he said and disappeared out the door.

A few minutes later, the goblin returned with Mr. Snag at his side.

The caretaker’s face was pale and his thick hair matted and standing up on one side. He’d been locked up for less than a day, but already he looked years older.

“Tank! Fizz!” His wide smile couldn’t hide the weariness in his eyes. He slumped into the chair on the other side of the table. “Nice of you to visit an old troll in trouble.”

“We want to help you, Mr. Snag,” I said.

“You didn’t release the slimes, did you?” Tank asked.

“Of course not! They’re like my children.” He shook his head. “My poor slimes.”

“Tell us what happened,” I said. I pulled out my detective notebook. Really, it’s my math homework book, but not a lot of math gets done in it. Like I said, homework and I don’t see eye to eye.

Mr. Snag sat up straight. “I locked up the school as usual. I went home, read a book and went to sleep. When I got to school in the morning, the slimes were already slurping around the playground.”

“Was there anyone with you at home last night?” Tank asked. “If someone was with you, that would prove you didn’t come to school in the night and release the slimes.”

Mr. Snag shook his head. “Nope. Just me and a good book.”

There went that alibi.

“Did you lock the door when you left the school?” I asked.

“Like I always do. Double-checked it and every-thing.” Mr. Snag didn’t hesitate with his answer.

“The lock on the front door was not tampered with,” Tank said. “Whoever let the slimes out had their own key.”