It wasn’t hard, really. I took an X-Acto knife, clicked it up until it couldn’t go any further, and slit my shoes open along the seams. I made a mold of the soles, filled it up with a thin layer of rubber and then as much plastic explosive as possible, and then hid the transmitter in the steel toe caps. More explosive went in the fabric too, where I had cut the seams. All of it was made to fit the shape of the shoe so it wouldn’t show up in the x-ray scanner.

Simple, but a beautiful piece of work. It was at least enough to blow a hole in the cabin, and that alone would destabilize the plane.

Then the tickets. Row 14 economy, right next to the left wing. The left engine.

As I took my seat, I noticed a man—maybe mid-thirties—take the seat across from me. He wouldn’t have caught my attention, but he kept glancing my way. And for some inexplicable reason, I had the first flutter of doubt.