Derek does a doubletake, having not expected his gaze to land on Lydia Martin's form when his eyes followed in the direction his sister was pointing. She certainly looked like Lydia, but the scent was all wrong. No banshee in it, no distinct aromas that marked her as Lydia. Just a face that could have her pulling off a missing twins act with Isaac's look-a-like.

Just how many people on this ship looked like people they knew, anyway??

"That's disconcerting." Mary Jane; not you, little sister.