I grabbed a rag and dampened it under the faucet. A thick layer of dust sat in the grooves of the open window, tinged green from all the pollen wafting through the air. I cleaned it out and moved on to the overhang of wooden trim that went around the entire room. Dragging the cloth along, I made my way back behind the closet-sized drying rack.

A frayed piece of the rag caught on the trim where it had come away from the wall. I yanked hard, trying to pull it free. It broke loose with a soft click, and a small, narrow door opened in front of me. A gust of sweet-smelling air wafted out.

“Mom! Mo!”

Mo came first, holding a kitchen knife, and Mom barreled in behind her, her Taser crackling in the midmorning sun.

“What is it?” Mo asked frantically.

“Look!” I pointed toward the door. Its seams were perfectly aligned with the wood paneling. Nobody looking at it would have even known it was there. “The rag caught on some kind of latch when I was dusting. It just popped open.” Mom pulled me back a step.

“Wait a minute,” Mo said. She hurried out of the room and came back a moment later with a flashlight. She clicked it on and shone it into the room behind the door. The column of light cut through the darkness to reveal a space the size of a large bedroom. There were no windows or other doors. Mo stepped in and Mom and I followed her. The walls were painted black, making the space feel smaller than it actually was. The sweet smell was more pungent inside the room. It reminded me of honey and burned paper.

There was a small table at the back of the room. As we approached it, the light from Mo’s flashlight danced in her trembling hand.

“What is this?” Mom asked, her voice barely a whisper.

The surface of the table was covered in a black cloth. In the center was a large statue of a woman with three faces—Hecate, the goddess Medea was in service to. Objects were arranged on the table: three rusted skeleton keys, bundles of what I was sure was mugwort, garlic skins, black candles with trails of wax that had run down and dried in layered mounds, and onions that had sprouted and snaked across the black cloth before rotting away to almost nothing. There were small bowls, black stones, and a wreath of decayed flowers around the statue’s neck—even a glass jar stuffed with black bird’s feet.

“It’s an altar,” Mom said.

“Auntie Leti has one,” I said.

“But it’s not like this,” she replied. “Hers is for working, for . . .” She trailed off. Her eyes narrowed and I followed her gaze. Sitting at the base of the statue was a photograph, ripped on one edge and stained brown at the bottom like something had spilled across it, soaking it all the way through. I immediately recognized the bubbly little girl, no more than a year old.

It was me.

Mo reached for it, and Mom caught her by the wrist. “Don’t touch it. Don’t touch anything.” Her voice was higher, her face drawn tight. Mom pulled out her phone and dialed a number. “Leti, I—I need your help.”

I didn’t like the way she sounded. There was real fear in her tone, and I suddenly became uneasy. Mo came and stood next to me, putting her arm around my shoulder, and I hugged her tight.

“There’s an altar in this house,” Mom said on the phone. “There’s a statue of a woman with three faces.” She paused as Auntie Leti asked her a question. “Garlic, onions, black flowers, crow’s feet.” Her face relaxed as my aunt spoke. “Leti, hang on, I’m putting you on speaker.” She held the phone out. “Go ahead.”

“This isn’t my practice, Thandie. You know that.”

“I know,” said Mom. “Just tell them what you told me.”

“The triple goddess is Hecate. Also known as the Queen of Witches, Keeper of the Keys, Guardian of the Crossroads. In Greek mythology, she’s said to have aided Demeter in her search for Persephone.”

The hair on the backs of my arms stood straight up.

“She’s ancient,” Auntie Leti said. “An original goddess, or an entity that the goddess label was slapped onto because they didn’t have a name for what she was. The black flowers, the crow’s feet, black stones, candles—those are all for her. Like an offering. She’s often said to be accompanied by a black dog. She’s the guardian of women and children, so I wouldn’t be overly concerned.”

“It’s too late for that, Leti,” Mo said.

“There was a picture of Briseis on the altar,” Mom said.

There was a sharp intake of breath and a long pause.

“Take me off speaker,” said Auntie Leti.

Mom talked to her for a few more minutes, while Mo moved behind me to examine something on the wall. “Briseis, look,” she said.

Something was drawn there—an intertwined maze of twisting lines, like vines, each new leaf bearing a name. There were hundreds of branches, each bough sheltering dozens of generations beneath it. “Colchis” was painted in a flowing script at the very top, and directly underneath was the crest—from the hidden door in the Poison Garden, from the desk in the room behind my fireplace, from the drawing Mrs. Redmond had given me.

“Shine your light up there,” I said.

Mo pointed her light at the top of the wall. The unmistakable face of Medea emerged from the gloom, her dark eyes staring down at us. Her name was written under her portrait, and every branch stemmed from her. She was the founder of this family tree. I traced the branches until I found, near the bottom where the leaves were sparse, my name nested under Selene’s: Briseis Colchis.

Mom came up behind me and seemed to take in the wall in one sweeping glance. “Baby, this is incredible. Look how far back this goes.”

I scanned the wall. Near the top, directly to the right of Medea’s painted face, was another portrait—a man. His branches intermingled with Medea’s, but abruptly split off.

“What did Auntie Leti say?” I asked.

“She’s gonna get back to me,” said Mom. She exchanged glances with Mo, who nodded, and they steered me out of the room.

“That tree goes back so far,” Mo said. “You really think this is real? I mean, how can we know for sure?”

It was real. It had to be. There was a reason my blood woke the Heart from its slumber. My blood was Medea’s blood, and she had been the plant’s original guardian. I needed to tell them about that and about me. It couldn’t wait anymore. “Listen, I have to tell you something and it’s going to sound impossible but it’s important.”