Invasion!

S5, E8: In the 100th episode and second part of the epic Super Hero Crossover Oliver wakes up to a life where he never got on The Queen's Gambit. Robert (guest star JAMEY SHERIDAN) and Moira Queen (guest star SUSANNA THOMPSON) are alive and well. Laurel (guest star KATIE CASSIDY) is his loving fiance and their wedding is imminent. Everything seems perfect but Oliver starts to notice small imperfections that make him question this new reality. Meanwhile Felicity and the Recruits take on a new threat with help from The Flash (guest star GRANT GUSTIN) and Supergirl (guest star MELISSA BENOIST).