Gemma Angel is an expert on tattoos. Except, she doesn’t know who the ones she studies belongs to, or really why - because they are the last remains of people who died over a century ago. Angel is the PHD student chosen by University College London and the Science Museum to unravel the mysteries behind a macabre collection of tattooed human skins acquired by the Wellcome Collection, a London museum specialising in medical artefacts, 80 years ago.