Board Thread:False Info and Speculative Discussion/@comment-25550807-20141104043221/@comment-6383956-20150531042437

They could always use the explanation Buffy used to explain Willow sticking around -- she wantef to help fight the evil supernatural beasties that plagued the town. Lydia has constantly striven to use her abilities to do that -- to prevent people from dying, rather than just finding their bodies. It's not a stretch to imagine she'd stay in Beacon Hills to do just that.