If Max found out about my memory, he would make my life a nightmare. I could never go back to the stables, and I don’t know what I’d do if I couldn’t ride. Encouraging me to ride was another gift of Gram’s. And when she saw how much I loved it, she talked Dad into buying Remy for me.

I study every story on the Internet about people who have HSAM. Their stories make me feel a little less alone, and it’s amazing to hear how similar my memory is to theirs. Most didn’t even know their memories were different until they were about my age, so at least I’m normal in this area of my life. One woman said her memory grew each year, until she could remember every second of a day in the blink of an eye.

It feels strange to read about scientists studying the brains of people with HSAM. What are the odds I have the kind of memory that could help someone who is losing theirs? What if my memory actually holds the key to helping Gram?

I imagine myself strapped to a table with wires connecting my brain to Gram’s. I would give Gram all of my memory—every bit—if it kept her from forgetting me. I never want to see her look right through me like she did last Wednesday. Not ever again.

It happened right when it was time to drive me to my riding lesson. Gram had just locked the front door. The keys slipped from her hands and fell on the porch, so I scooped them up and handed them back.

“Why am I here?” Gram asked, looking from the keys in her hand to me. She stared at me blankly, frowning like she didn’t trust me. Like I was a bug crawling across the floor. A bug she didn’t recognize.

A pulse drummed against my forehead. “To take me to riding,” I answered.

I was used to how Mom looked past me, as if she were seeing another little girl from another time and place. Or how Dad kept his eyes glued to his phone, pausing to glance at Clay or me with an absentminded smile. They love me, but they don’t see me. A piece of their heart is locked away—maybe forever. But with Gram, Clay and I have her whole heart. Every part of us is important to her.

Except now Gram’s brows stayed furrowed. Her cheeks turned pink, and then a bright red stained her neck and chest. “I know you?”