The finale is titled "Mad Idolatry" and will air on December 7th. Here's the synopsis:
Ed and Kelly seriously reconsider getting back together. However, while Kelley is on a mission with Isaac and Gordon to investigate the origins of an uncharted star, they suddenly crash-land on a planet from another universe. Kelly then makes a decision with unforeseen long-term consequences for the planet, putting Ed in a difficult position in the all-new "Mad Idolatry" season finale episode of THE ORVILLE airing Thursday, Dec. 7 (9:01-10:00 PM ET) on FOX. (ORV-113) (TV-14 L, S, V).
It shouldn't be surprising to fans who have been following The Orville that Ed and Kelly's relationship will be at the center of the show's first season finale. While The Orville has been almost entirely episodic in its story structure but if the season does have a season-long arc its been the arc of Ed and Kelly's relationship. Their divorce is what kicked off The Orville, it makes sense that presumably bringing some closure to that relationship is how the season ends.
There's certainly some new information to unpack. When Kelly was first made Ed's first officer he definitely was not happy. However, he quickly grew to allow his professional respect for her as an officer of the Planetary Union outweigh his bitterness over her infidelity. Early on it even seemed like they may give the relationship another chance, but then backed away.
A new wrinkle was thrown into the mix when Darulio, the blue alien whom Kelly slept with, arrived on The Orville for a mission. Darulio revealed that his species goes into a kind of heat that makes them irresistible to anyone they touch. He also hinted that he may have been in heat during his relationship with Kelly.
Ed and Kelly haven't really dealt with the new information, so fans will have to wait and see how things wind up for the couple in the season finale.
The Orville airs Thursdays at 9 p.m. ET on Fox.