Was adventuring with Lydia through a Dwemer Ruin (can't remember which one), after a fight with some Dwarven Spiders she's disappeared. No body, no pile of ash, nothing. I continue on, hoping she'll respawn soon, she never does. Make my way through the ruins, head back home (Vlindrel Hall, Markath), still no sign of her. Putter around in the city for a few days, Enchanting and Smithing, hoping she'll catch up, still no sign. I checked the Halls of the Dead in Whiterun, to see if her corpse has shown up there, but there's nothing.

Ideas?