Gal Gadot's Wonder Woman stole the show in Zack Snyder's Batman vs. Superman: Dawn of Justice, before garnering major plaudits for her origins. However, DC's cinematic universe was deviating from the superhero narrative norm, telling her story in reverse, moving from the team-up with Batman and Superman, backwards to how Diana of Themyscira became the iconic heroine.
In BvS, what stood out was that Wonder Woman made it clear she fought entities from other worlds prior to Doomsday, which smartly set her up for stories before DC's Trinity united. What was also notable was that Diana gave the impression to Batman that she retired or was just disenchanted with being a hero from years before. However, at the end of Patty Jenkins' film we saw Diana as Wonder Woman, all too eager to embark on her newfound career as a superhero.
So what happened in between these two movies that basically made her a hero that the world either forgot, or one who wanted out of the limelight? Well, if we go back to BvS, she agreed with Bruce that they needed to start the "age of heroes" again which meant that it existed before. Jenkins subsequently stated that her sequel would be set in modern times and focus on a "classic" Wonder Woman, which leaves a few possibilities regarding her whereabouts during this period.
The '80s has been mentioned as potential stomping ground which could revolve around Diana facing the Soviet Union in the final days of the Cold War. Jenkins could even change her mind and go further back to World War II. With Chris Pine returning, rumors are he'll reprise his role as Steve Trevor, despite dying at the climax of the first film. It remains unclear how the sequel will bring him back, but he can appear in flashbacks, visions or as the original Steve Trevor's distant relative. The thing about going this route of having him team up with Wonder Woman again, though, is that it would feel repetitive.
Jenkins already went in depth into their relationship and honestly, everything was covered, so there's nothing new that flashbacks would show us that we haven't already seen. Don't get us wrong, Pine's chemistry with Gadot was very strong and we would love to see them back again, but another period piece steeped in the trenches of war may end up stale. Differentiation is needed.
This is where Diana's comments about fighting otherworldly creatures could factor in, with this gap exploring her ancestry. In Wonder Woman, we got a glimpse of Zeus and his pantheon of gods, so what if Diana's journey sees her diving into her lineage? Imagine if Zeus was alive and simply playing god, allowing his kids to dictate the fate of man. There was no real confirmation that he died in the first movie and in any case, he's the god of all Greek gods, so we're certain he can be revived. Perhaps Greek mythology is where Diana fought creatures such as Medusa, the Harpies or even the Minotaur.
This can also offer expansion on the relationship between the gods and the Amazons, perhaps even analyzing new territory such as her half-brother, Jason, as seen recently in DC's Rebirth, and creating room for other demigods such as Hercules to enter the fray. This would also offer a new dimension to Pine's return because Diana could find herself meeting her dead lover in Hades' underworld. Maybe leaving Steve behind in the land of the dead or believing that Ares may have been right about mankind may have helped push her into a hiatus. Believing the world isn't worth it would be a hell of a place to leave her but it would also set her up to be inspired to return to action by superheroes like Batman and Superman.
Exploring other worlds doesn't have to be limited just to the Greek gods because this could also mean DC's New Gods. Orion, Darkseid's son, played a big role in Greg Rucka's recent stories with Wonder Woman, and a sequel could see her going back home to explain the world of man to her people, only for mysteries of the Mother Box to unravel. This can sew seeds for the existence of the Anti-Life equation, New Genesis and Apokolips, and radicals such as Mister Miracle, Big Barda and the Infinity People.
Peering into a larger scope of gods may even hint at Grail (Darkseid's daughter with an Amazonian). We already saw Diana fight a corrupted Steve in the Darkseid War comics thanks to Grail so using him as a villainous foil, similar to how Bucky Barnes was brought back as the Winter Soldier, presents another intriguing angle. Jenkins could also find herself adding connective tissue here in between Justice League movies while still keeping it a self-contained Wonder Woman story.
The gap between films can also send Diana back home, defending Themyscira from other non-godly threats like Giganta or Cheetah, or mystical villains like the evil witch Circe. Then, there's the simpler plot with soldiers who are looking to discover, invade or destroy Paradise Island, which begs: what if these men actually succeed? Seeing her world destroyed by the people she vowed to protect could also shatter Diana's faith in humanity. A hero who no longer wants to fight for mankind, or who maybe harbors resentment towards them, would add a fresh twist to the plot, especially if it leaves Diana as the last daughter of Themyscira.
Fans want to see Wonder Woman tested, not just physically, but mentally. Wherever she was, Jenkins must show Wonder Woman questioning her purpose, thereby acting as the prologue for BvS and Justice League.