Marie pretended she didn’t hear him, and he shoved his hands in his pockets, glancing around nervously. I walked through the Poison Garden and stopped in front of the rear wall. The vines pulled back, and I opened the hidden door. The crimson brush bloomed and pointed toward the door. I held up my hand. The plant retreated.

“Ready?” I called to Karter. “Hold your breath and run. Now!”

Karter sprinted forward, stumbling once and nearly falling flat on his face. Marie was suddenly there, hoisting him up and pulling him toward the door. They slid to a stop in front of me.

“Oh, wow,” Karter said, staring down at Marie. “You work out?”

I yanked him through the door and Marie slipped in after him. I stood between them and the crimson brush’s star-shaped blooms.

“Down there,” I said, gesturing to the stairs.

They disappeared below and I followed once I was sure the crimson brush wasn’t going to act up. I descended the stairs into the dank little room. Karter and Marie were both completely silent. The lights from our phones illuminated the small space. The plant stood in its glass enclosure. Karter leaned in and I quickly put my arm in front of him.

“This is the Absyrtus Heart,” I said. “It’s the deadliest plant I’ve ever come in contact with. I don’t want either of you to get hurt. You shouldn’t even be in here, but I had to show you this. It’s real. It exists.”

I examined the hole in the ceiling, and Karter followed my gaze.

“I think when the moon rises, it shines through there,” I said.

“What kind of plant grows in the dark?” Karter asked. “Don’t plants need sunlight?”

“Queen of the Night cacti only bloom in the dark.” I unlocked the glass door and we peered inside. “But this is something else.”

Marie stood as still as the shadows. “I don’t even know what to say.”

I’d felt the same way when I first saw it. If I hadn’t seen the shriveled stalk and crumbling leaves underneath it, I would have thought I was looking at a real human heart, somehow preserved.

For my AP Biology class, we’d taken a field trip to the museum and seen a human heart suspended in a jar of formaldehyde. We’d had to label the parts on a worksheet, and all those parts were there on the strange plant. The flat waxy plain of the right and left ventricles was pointed upward. The tangle of what might have been arteries snaked off the bottom and fed into long, thick stalks.

Karter leaned over my shoulder. “What the hell? Have you tried watering it? Tried to get it to come back like the stuff up top?”

“No. But I don’t think water would make a difference. I don’t think that’s what it needs.”