They moved to a control panel at the far end of the hallway. Moments later, bars began to swing open with a series of loud clunks, and Plexiglas doors slid to the side.

The prisoners stepped uncertainly into the hall. Their subcutaneous magic-dampers played havoc with my tattered invisibility spell. “My name is Isaac Vainio. We’re going to get you out of here. There are other prisoners, a group of sirens. Have any of you seen them?”

A few of the prisoners shook their heads. The rest were silent.

“They’re gone.” That was the other guard, Johnson. “Left about two hours ago. We’re not equipped to hold marine species long-term.”

Deb swore and hammered her fist against the wall. “Why bring them here at all, then?”

“Tagging, scanning, and cataloging. The computer equipment is state of the art. Examinations that would normally take hours are automated, and—um, why is that ghost dude on fire?”

Heat seared my ear. I craned my head away from Smudge as well as I could, but I was pretty sure he’d blistered the lobe. “We’re about to have trouble.”

“There.” One of the prisoners pointed to the broken door behind us. I saw movement beyond, and then a shotgun barrel poked through.

Deb was already shoving the closest prisoners back into their cells. She threw herself to the floor as the first gunshots rang out. I followed suit and rolled up against the wall, being careful not to squash Smudge in the process.

Lena strode past me, one arm outstretched toward the oaks she had grown in the doorway during her initial attempt to break through. They creaked and twisted to life. Branches twined around the gun. Lead shot thudded into Lena, but none penetrated her oak skin.

Several branches cracked and broke, weakened by the guards’ badges. The tree continued to grow, weaving new branches through the doorway in a thick wooden web. Leaves sprouted from the branches, further obscuring us from view.

“Hold fire,” someone yelled from the end of the hall. “You’ve got no way out. This is your only chance to surrender.”

“I can’t hold them very long,” Lena said quietly.

I could hear the guards pulling and snapping the branches of her makeshift barrier. With their badges siphoning Lena’s magic, her tree was little more than mundane wood. She gasped in pain at every broken branch.

I looked around, trying to orient myself. If this was the north cell block, the walled yard I’d seen was on the opposite side of the facility. My enchanted compact mirror wasn’t big enough for anyone except maybe Smudge to escape through, even if I’d been confident in my ability to set a destination I couldn’t see. The devourers would stop any magical attempt to break through the outer walls.

That left making my own door as the only option.