Greg and Bella are joined by award-winning Biology teacher Miss Wilsher for a lesson all about tattoos! By looking at how a tattoo works, we'll find out about the different layers of your skin and how pain works; we'll also hear about the chequered history of tattooing and it's ancient origins. Lacrosse-fan Miss Wilsher will share the science behind why a tattoo stays put, how to stop them fading and - at the other end of a tattoo's life - how laser removal works. Otzi the Iceman makes a reappearance, and Greg and Bella will share their own tattoo stories - from embarrassing first tattoos to Greg's blink-and-you'll-miss it wrist tattoo.