S7, E22: Buffy comes up with a plan: The gang makes an attack on the First's army, aided by Willow, who performs a powerful spell to imbue all of the Potentials with Slayer powers. Meanwhile, wearing the amulet that Angel brought, Spike becomes the decisive factor in the victory, and Sunnydale is eradicated. Buffy and the gang look back on what's left of Sunnydale, deciding what to do next.