With the UN and FBI suspecting that there are up to 750,000 people online at any one time hunting for children to exploit, how can the booming cybersex trade be policed effectively? Kicking off BBC Three’s Gender Season, Stacey Dooley presents the first of two hard-hitting films from some of the worst places in the world to be female. She investigates why some young women today live in such dangerous, desperate and degrading conditions. In this episode Stacey travels to the Philippines - fast becoming the world capital of the cybersex industry. Here, girls who are rarely let out and often underage must perform on webcams and be photographed for a global online audience. Within the last year alone, 139 Brits were investigated for paying to watch Philippine children being abused. Stacey learns how poverty combined with cheap internet access has led to an increasing number of girls being exposed to online sexual abuse. Discovering the harrowing truth behind this widespread exploitation, Stacey then exposes an even darker side - cybersex dens. We see Stacey at her best as she goes undercover for the first time and follows the police on a major sting, bringing her face-to-face with the criminals behind this new and disturbing phenomenon. She also travels north of Manila and learns that efforts are being made to help some of the 100,000 victims of exploitation, using therapy and counselling from psychologists - some of whom have suffered the same abuse as the children they are helping. Stacey is overwhelmed at the sheer scale of this billion dollar industry, but remains hopeful that if police forces across the world work together, there's a chance this secretive trade can be tackled.

• Stacey Dooley