You were out exploring an abandoned gem mine. It was abandoned because it was said that some people who enter go missing and those who do come out immediately quit their mining job due to fear. Regardless, you entered to see what was going on. You then encountered a shiny red gemstone on the ground. You picked it up to get a better look at it. Suddenly, it shot to your belly and attached there. Before you could make any sense of what was happening, you transformed into a curvy Anthro Sableye girl!