Even though the Season 4 premiere of the Flash focused on getting Barry Allen (Grant Gustin) back home and making Team Flash whole again, there remains a mystery. Where has Caitlin Snow (Danielle Panabaker) been, and what are her ties to Norvok (Mark Sweatman) and their boss Amunet, AKA The Blacksmith (Katee Sackhoff)? But don't expect those answers to come right away.
What we will see is Caitlin struggling to not go frosty at a very inopportune moment. Panabaker also told TVLine recently that with her return, there are a lot of unresolved issues between her and Iris West (Candice Patton) stemming from Savitar trying to kill Iris and Killer Frost helping him do so. But she hopes there can be healing, which I would expect to start taking place in the Girls Night Out episode where we'll get to meet the Blacksmith.
As a bonus, Matt Webb Mitovitch of TVLine has already seen the second episode of the season and says that it is very funny and keeps with the light tone that we were promised for the new season. He also promises one of the show's most hilarious sight gags ever, and that Barry's worst foe in that moment would be his best friend Cisco Ramon (Carlos Valdes).