Inside Beck’s office, the air was thick with the scent of the lemon air freshener Myla loved and the relentless, looping sound of a dead woman’s laughter. The walls were covered in projections of Rosie Kowalsky: at a picnic, blowing out birthday candles, looking into a lens with bright and hopeful eyes that knew that she was going to be erased in such a horrible manner.

“Again,” Beck said with a soft voice. He was perched at the console, his glasses reflecting the blue light of the ...