It was a San Francisco Chronicle article about a medical student, Andrew Shaw, who had died in Uganda the previous week in a bushfire. He had been working for the WHO on an AIDS awareness campaign. I recognized my son’s face, but I didn’t want to believe it. Yet underneath the article were several photos of his burned body. Tears streamed down my face.

A handwritten note on a scrap of paper was also in the box.

Leave us alone, or the other two will be next.

Happiness and fear fought a war within me. Andrew was dead. Madison and Peyton were alive. But what of Lin?

I left that night, and I went deep underground. Off the grid. I never stopped researching the Citium, but I did it in a passive way now. I kept a folder on every known Citium cell, and year after year, I gathered more and more information. Several cells had survived the purge, and one of them was responsible for the slaughter. But I didn’t know which.

I had gained one thing from Andrew’s death: a last name. And with that single clue I discovered that Lin was alive in America. I debated for weeks whether to contact her, but finally decided against it. I followed her career at Stanford. I celebrated when Peyton was accepted to medical school. I cut out Madison’s wedding announcement. And years later, I saw my children for the first time in twenty years: on YouTube. I watched videos of Peyton, sometimes for hours. She had grown into a fine woman, a wonderful doctor, with her mother’s passion for her work. She reminded me so much of Andrew; I wondered if his death had influenced her career path.

I longed to reach out to her and Madison and Lin, but I knew it might put their lives at risk. Those years after 1991 were like prison for me. I dreaded the future. I saw the life I could have had slip away. I never got to be the father I wanted to be for my children, or a husband to Lin. My life was torture, but I held on to hope, and I prepared for a day when I could stop the Citium. Or, in the worst case, when they would find me—or force me to act.

Unfortunately, the worst case has indeed come to pass. As I write these words, our opportunity to stop them is slipping away.

Stop them. Don’t give up. Use everything you know, take nothing for granted, and trust no one.