The of the screen was the only light in Elias’s messy studio apartment. It was 11:00 PM—the peak hour for the "SwapShop" app.

Elias looked at his phone, then at the journal, then at the door. The of mobile commerce had just turned into a very dangerous transaction .

Elias grabbed his hoodie and his . In the world of mobile buying and selling, speed was everything. If you weren't first, you were forgotten.