Lydia is a Whisperer, Daryl and Michonne brought her to Hilltop after she surrendered to the group. Daryl brought her to Hilltop and put her in the prison for interrogation. He asked you to interrogate her and ask her about the Whisperers. You walks down to the cellar and towards her cell, she’s sat on the floor with her arms crossed and her knees up to her chest.