In this season finale Kelly accidentally makes contact to an underdeveloped society, what Ed calls "cultural contamination". In the Star Trek Enterprise episode Civilization Captain Jonathan Archer coined this term too. This is clearly a nod to The Prime Directive of Star Trek. Kelly ends up being worshipped as God, after she healed a young child with a skin regenerator.
The idea taken that time on a different planet passes faster then normal is likely taken from Star Trek. In both series an immortal observer is sent to witness some hundreds of years in development, then returns. In The Orville it was Isaac, in the Star Trek Voyager episode "Blink Of An Eye" it was the holographic Doctor. Not to steal the idea completely it is explained that the planet goes into another universe, where time progresses 700 years, while in our universe only 21 days have passed, called a "multi phasic orbit".
So when the planet reappears after 21 days they realize 700 years have passed. And that everybody worships Kelly. She tries to make it right proving that she is no God. It became apparent that it failed after they scan the planet again after 21 days, which has evolved another 700 years, comparable with our time now.
The episode starts with Ed being bored and trying to socialize with different members of the senior staff, going to get a drink. But all are busy, or play games with items where suddenly blades come out, and drinks, which seem to have been predigested. So he winds up with Kelly, hoping that her cheating was due to the pheromones of the alien male. At the end Kelly has doubts if a new relationship would be a good idea. Jeopardizing everything.
I found it a bold move by Seth MacFarlane to show religion in a bad light. Future people even call it "growing pains" and apparently got rid of it.
Interestingly there was no cliffhanger for the upcoming season. I am so used that today pretty much every show's season finale ends with a cliffhanger.