Partial-gem twins Mabel Dioptase and Dipper Diopside Pines are sent to live with their gem of a grunkle, Stan, to keep them safe while their hometown is overrun by gemmed monsters. As their dad fights them off, Mabel and Dipper must figure out their magic before they can go home, and unlock the secrets of Gravity Falls along the way. (Gravity Falls full-series rewrite for an AU)