"Invasion!"ARROW CELEBRATES 100 EPISODES; THE EPIC SUPERHERO CROSSOVER CONTINUES — Oliver (Stephen Amell) 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 fiancée and their wedding is imminent. Everything seems perfect, but Oliver starts to notice small imperfections that make him question this new reality. Meanwhile, Felicity (Emily Bett Rickards) and the recruits take on a new threat with help from The Flash (guest star Grant Gustin) and Supergirl (guest star Melissa Benoist). James Bamford directed the episode with story by Greg Berlanti and written by Marc Guggenheim & Wendy Mericle (#508). Original airdate 11/30/2016.