Board Thread:WARNING ALL USERS False Info\Spoilers/@comment-16263916-20130823002807/@comment-4091815-20130823172957

Ravensong77 wrote: I find it interesting that Lydia's birthday just happened to be Peter's last chance to resurrect...and he also evidently knew she was immune...He could have easily found out her birthday (still think it's weird that it just happened to be the exact date he needed). I just hope they eventually tell us how he knew she was immune.

It wasn't the "exact date" he needed - he just needed a full moon.