Warning: spoilers ahead for the sixteenth episode of Agents of S.H.I.E.L.D. Season 5, called "Inside Voices."
Agents of S.H.I.E.L.D. has gone in some wild directions in Season 5, and the show only seems to get wilder with each passing episode as the agents struggle to find a way to prevent the world from being destroyed. There are a lot of variables currently in the mix, ranging from Ruby and her claim to the title "Destroyer of Worlds" to Daisy and May's determination to use Robin and change the timeline to Fitzsimmons' and Yo-Yo's absolute conviction that they can't die to gravitonium somehow being alive. Throw in the facts that Coulson is dying and Hydra is still somehow in the mix, and the status quo is a mess for the good guys.
Now, "Inside Voices" may have made things even messier with the returns of two characters who haven't been seen for a while, and their appearances may tease the return of a long-lost character with the potential to save the world: Dr. Franklin Hall.
Here's what happened. "Inside Voices" added a new wrinkle to what we know about gravitonium when General Hale exposed Creel to gravitonium to see what would happen. He confirmed that gravitonium is somehow alive, and he proceeded to have visions throughout the rest of the episode before (presumably) meeting his end at the hands of Ruby. S.H.I.E.L.D. hasn't spent much time on how gravitonium is alive/allows people to survive in it, but it looks like the show is gearing up to deliver a lot of info.
The tease for what could bring back Hall came in the tag, which was a blast from the past that took viewers back to a scene between Raina and Ian Quinn. It seemed to be set immediately after Quinn took off at the end of the Season 1 finale with a box of gravitonium. Unfortunately for Quinn, Raina had motives other than letting him escape with his life and a stash of the valuable element. Instead, she opened the box and allowed him to be consumed by the gravitonium, which apparently took no interest in her. The gravitonium wanted Quinn, according to Raina.
On the one hand, the scene really seemed to indicate that Quinn could be the game-changer in the agents' fight to save the world, which will undoubtedly be a fight that requires a greater understanding of gravitonium. I certainly won't rule it out. That said, it could also be the first hint that S.H.I.E.L.D. is bringing Dr. Hall back into the mix, and he might be more inclined to help the agents than Quinn would be.
In case you've forgotten about Dr. Hall, he was a scientist who appeared in exactly one episode way back in Season 1. He was an expert on gravitonium, and he got himself "kidnapped" by Quinn so he could have access to Quinn's stash of the element. Quinn intended to weaponize the element; Hall intended to stop him from using the gravitonium that way, even if it meant killing a lot of people. S.H.I.E.L.D. stepped in, but Hall seemingly perished when a fight with Coulson ended with Hall falling into gravitonium. It was later revealed that he was alive somehow within the gravitonium, trying to get out.
As an academic expert on gravitonium who once was willing to do anything for what he saw as the greater good and who presumably has a greater understanding of the element after spending years suspended in it, Hall could be the perfect person to help the good guys figure out how to stop gravitonium from probably contributing to the destruction of the world. Sure, the agents would have to figure out a way to pull him out of the gravitonium, and there's still too much we don't know about gravitonium to predict exactly how this would work, but it would be a killer way for S.H.I.E.L.D. to tie off a loose end and provide an answer to a major question regarding preventing the end of the world in Season 5.
That said, if Hall does return, he may not actually be inclined to help. The man may have lost some perspective after being stuck in gravitonium for years, and he's had plenty of time to nurse a grudge against Coulson. There's also the point that the Dr. Franklin Hall of Marvel Comics lore became a supervillain known as Graviton with the ability to control gravity. If Hall ended up as Graviton, his return would just be one more problem for the agents! We'll have to wait and see what happens. At this point, is any theory too crazy?
New episodes of Agents of S.H.I.E.L.D. air on Fridays at 9 p.m. ET on ABC. The ratings for Season 5 aren't the best and we can still hope for a renewal, but the folks behind the scenes at S.H.I.E.L.D. wrote the finale in a way that could satisfy fans whether the show is cancelled or not. For what you can watch now and in the coming weeks, take a look at our midseason TV premiere schedule and our summer TV premiere guide. If streaming is more your style, swing by our 2018 Netflix rundown and 2018 Amazon Prime breakdown.