“Yeah,” Theo said. “It was probably just hanging out in its fish fortress.”
“Cretaceous castle,” Mom said.
“Monster mansion,” Theo countered.
The creature leapt from the water—fans stretched like moist wings—and bared its teeth at us. Then it slapped the rail hard enough to warp the metal. It roared before hitting the water again, then slid under with hardly a splash. And the rail gleamed with dark, iridescent blood.
“It’s hurting itself,” I said.
“It will probably keep fighting until it kills the demon, or the demon is gone, or the demon destroys it.” Uncle Catcher’s voice was grim.
“There has to be some kind of prearranged signal, so it will know when to stop attacking,” I said. “Something the Guardians did.”
“This is why you should always leave instructions for your replacement,” Theo said. “It’s common courtesy.”
“Have you tried—I don’t know—talking to it?” I asked.
They all looked at me like the suggestion was insane.
“Considering our biology and jobs, not really our place to get judgy about supernaturals.”
“This is now a rescue mission,” I said. “Saving the creature from himself.”
Theo pulled out his screen. “Petra,” he said a second later. “Chicago river monster. How do you send it back to its home or put it back to sleep or whatever?”
Her squeal of excitement was loud enough for all of us to hear.
“Lizard lair,” Aunt Mallory quietly offered.
I guessed she was the kind of worn down and tired in which everything had better be funny or she wouldn’t be able to stop the tears. And I wished I had more to offer her.
“Dino den,” Theo murmured.
“Oooh,” Petra said. “Is that the fourth ward? A river monster?”
“A leviathan,” I suggested. “Big, wet, pointy bits.”
“Did you sing to it?” Petra asked, and we all looked at one another.
“No?” Mom said. “Should we?”
“Well, I’m not there”—and she sounded very disappointed about that—“so I’m going off my personal research, but usually your undersea supernaturals are responsive to sound.”
“I told you that you should’ve talked to it,” I said.
“Did setting off the ward make some kind of noise?” Petra asked.
“Bells,” Uncle Catcher told Petra. “Sounded like church bells.”
“That could do it. That’s probably the trigger the Guardians established for it. The sensor, which is probably near the bells, is triggered by demon magic, and when it sounds, the leviathan—let’s call him Levi—comes up to attack. Wait—are there demons near you?”
“Uncle Catcher accidentally tripped the ward with a test spell,” I explained, leaving Uncle Catcher to mutter his objections.
“It’s destroyed the Wabash Avenue bridge,” I said, “and taken chunks out of the Riverwalk, and it’s hurting itself in the process. So, we need to make it stop.”
“Well,” Petra said. “Thinking it through, we need it to go back to its resting state. To think the demon has been vanquished and it can go back into this good night.”
“Right,” Mom said. “I mean, that sounds right.”