In the second of his new series focusing on three American cities, Louis is in Houston, Texas.

He’s here to find out why the USA’s fourth-largest city is known as a hub for human trafficking, and to meet people caught up in its sex trade.

As the film begins, bold, confident prostitute Nikki declares that she’s got ‘the best job in the world’, but it’s not long before Louis sees the sadness and weariness behind the facade.

Why does she give all her money to her pimp when he uses violence to keep her in line?

Eighteen-year-old sex worker Savannah, meanwhile, is trying to quit drugs, but seems to be fighting a losing battle.

Affecting and very sad.