The fifth episode of The Flash is called Girls Night Out and will feature a guest appearance by Felicity Smoak (Emily Bett Rickards) and an appearance of Katee Sackhoff as Blacksmith. But who are the girls going out and why? Michael Ausiello of TVline asked executive producer Todd Helbing about that:
It’s really fun. The girls [including a visiting Felicity Smoak] go and have a night out in Central City alone, without the guys. And they get into some trouble.
He followed up by asking if the outing may be for a bachelorette party for Iris West (Candice Patton), to which Helbing said:
There are so many questions here. Who are ‘the girls’ in question. Does this mean that Caitlin Snow (Danielle Panabaker) is in control of her personality enough to have rejoined Team Flash by episode five? Or will she be some kind of Caitlin / Killer Frost hybrid? Will we see any other girls joining the party from the past? Patty Spivot? Kendra Saunders? Seems like there should be more than just three… and if there is a bachelorette party, will there be a bachelor party?
It would make sense, with everything that happened last season, for them to want to move quickly to get married. You never know when Barry might disappear into time or the speed force again.