There are some things I know for certain.

I am half-mortal, half-vampire. Some call me a hybrid, others a half-breed.

I was born in Saratoga Springs, New York, fifteen years ago. But this year, I turned twenty-two.

I'm a synesthete, apt to see words and numbers in color and texture.

The two friends closest to me both were murdered.

My name is Ariella Montero, and I know a secret. Telling it will change everything.

Once I had a friend named Kathleen. Although she was in my life for less than a year, I thought that she knew me better than anyone.

Sometimes we played a game called Anything in the World. Kathleen invented it. "If you could have anything in the whole world, what would it be?" she'd say.

The first time she asked me the question, I said, "I have no idea."

We sat in the belvedere, the summerhouse in our family's gardens in Saratoga Springs. It was June, and the air felt heavy with lavender, layered with the scents of white and yellow roses.

"Come on, Ari." Her face showed her disappointment-particularly her eyes, streaky grey, the color of water. Not gr ay. That was a stronger shade, more opaque, like lead.

I shook my head. "I can't think of a thing."

"Then you ask me." She lay back, relaxed as a kitten, against the cushioned seat.

I repeated the question: "If you could have anything in the world, what would it be?"

She pretended to think hard. She creased her forehead and stared across the room.

But I heard what she was thinking. The thought swelled so loud that it drowned her words, which said something else entirely: she wanted to be me.

Kathleen is gone now.

But years ago I saw her ghost in our garden, beckoning me to join her. Even now, sometimes at night I hear her voice, thin as water, silver as mercury, calling to me from a place I've never been, a place I can only imagine.