Oliver thought that he'd spotted her but so many times while he was on Lian Yu, he thought he'd seen people he cared about. Thea had often featured in those thoughts and seeing her here now...he wasn't sure whether or not to trust it.

"Speedy? If that's not you, you're going to have to explain why you look exactly like my little sister."

Maybe she had a different father from him but it didn't matter. Thea would always be his sister, his full sister, genetics be damned.