Hayley Pearce - lovable yet outspoken tea lady from BBC Three's Call Centre - is addicted to spray-tanning. And she's not alone. Nearly half of Welsh women and a third of Welsh men have self-tanned in the last 12 months. What's behind the triumph of the tan, and could there be a dark side to tanning? Hayley examines the rise in extreme tanning - 'tanorexia' - meeting tanning addicts, tanning experts and celebrity spray tanners. She investigates the illegal ways to fake it, visiting a science lab to learn just how toxic these unregulated products can be. And in a bid to understand the nature of her own addiction, Hayley attempts to forgo the glow and embrace the pale. It will be the first time she'll be her natural colour for over ten years, but how long can she last without her beloved spray tan?