Spoilers ahead

Whatever you were expecting from the concluding part of "The Orville" second season finale, chances are that it wasn't this. With the possible exception of " Identity part II " (S02, E09), more is probably crammed into this 48 minutes of television than any other installment. So sit back, temporarily suspend your belief in the laws of physics, forget for a short time the potential issues caused by plot holes, look for a wealth of subtle sci-fi references and enjoy this thoroughly entertaining episode.

Entitled "The Road Not Taken," it follows the events of last week's episode, where, if you remember, Kelly Grayson (Adrianne Palicki) has inadvertently altered the series timeline by choosing not to date Ed Mercer (Seth MacFarlane).

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The Kaylon now have the ability to, er, launch their heads as heavily armed drones. (Image credit: Fox)

As the episode begins, we see two masked figures trudging through a snowy forest; we have no idea who they are or where they are and some nice wide camera angles show us they're all alone. Eventually they reach a concrete structure — an outpost of some kind. Subtitles show us it's the Planetary Union listening post on Sarin IV. The two figures continue onward and manage to force the door to get inside; clearly whoever was once here has long since gone. They search the interior and one of them finds what appears to be a microwave oven. Their excitement is interrupted, however, as a Kaylon ship lands outside and three Kaylon emerge.

This is a stylish opening set piece and it's great to see an alien environment in "The Orville" that isn't obviously Griffith Park, the Santa Monica mountains or Seth MacFarlane's garden in the summertime. We can already guess we might be in an alternate future, but we're still intrigued. Sadly, though, this interesting new approach to the pre-credit sequence is spoiled slightly as the Kaylon heads sprout laser cannons — like we saw in "Identity parts I and II" and have never liked — but now the heads detach and fly off like drones. Why couldn't they just use actual drones? Not only does it look silly, but surely it would leave the respective decapitated bodies vulnerable?

The two figures dodge the laser fire from the … er, head drones. Thankfully, they don't appear to have very good aim, allowing the two figures to scramble safely inside what looks like a battered Union shuttlecraft. As they frantically work to get airborne, they remove their face masks to reveal that it's Mercer and Gordon Malloy (Scott Grimes). And the opening credits roll.

Straightaway, we're back with the shuttlecraft as it desperately tries to evade Kaylon laser fire. With the quantum drive offline, Malloy takes the shuttlecraft down into the caverns of a nearby ice planet in an effort to evade their deadly android adversaries. A combination of fancy flying and sharp shooting brings a wall of ice crashing down on the pursuing Kaylon death sphere, enabling our dynamic duo to escape.

Finally free of any threat, Mercer and Malloy connect up the microwave they have retrieved and we see that it's actually a food replicator. Risking life and limb to reheat last night's leftovers seemed a little excessive, but this makes much more sense. To celebrate, they replicate a Twinkie.

Grayson (Adrianne Palicki), Keyali (Jessica Szohr), Finn (Penny Johnson Jerald) and LaMarr (J. Lee) should really ditch those bland Union uniforms. (Image credit: Fox)

However, their junk food jubilation is short-lived as the shuttlecraft is suddenly caught in the tractor beam of a scavenger ship. Once aboard, the doors open and Grayson, Talla Keyali (Jessica Szohr), Dr. Claire Finn (Penny Johnson Jerald) and former Chief Engineer John LaMarr (J. Lee) step forward. It has to be said, they all look so much better in their ripped, rugged "Spacehunter"-style attire than those bland Union uniforms.

Mercer is somewhat surprised to see Grayson, since in this timeline she dumped him after their first date. Now, seven years later, here they are. Grayson explains what has happened; in essence, her mindwipe didn't work and she remembered everything that happened when she was transported into the future. Upon her return to her normal time, she decided not to continue dating Mercer – as we saw — and, long story short, he never became a Planetary Union captain. The Kaylon attacked and the USS Orville, under the command of someone else, failed to prevent the invasion.

"Half the known galaxy wiped out by those people … because we didn't go out again," Mercer says solemnly, after learning of the events of the nine months.

Grayson has been gradually getting everyone together in an ongoing attempt to set things right, and in order to do that, Finn must go back and correct the memory wipe. Apparently, the reason the mindwipe didn't work is that Grayson's brain is deficient in a protein called beta-secretase — something that Finn says could easily have been missed. With the proper injection, the mindwipe will take hold and history can be restored, but getting a hold of said proper injection will require a visit to the underground resistance.

This episode features some of the best VFX since the Battle of Earth against the Kaylon. Not only was the earlier ice cavern flying sequence impressive, but the scavenger ship must now navigate a treacherous asteroid field to reach the planet where the resistance is located, resulting in more gorgeous visual effects.

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Grayson, Finn, LaMarr and Mercer head down to the surface, while Talla and Malloy, plus Ty and Marcus Finn (Kai Wener and BJ Tanner, respectively), remain on board. The away team land on the planet surface and make their way to the resistance headquarters. And it's here that the first of several musical references are made within this episode.

Music often plays a big part in "The Orville" and we've seen – or rather heard — obvious references to John Williams and the music of "Raiders of the Lost Ark" in " Nothing Left on Earth Excepting Fishes " (S02, E04), plus the late, great James Horner and the music of "Star Trek II: The Wrath of Khan" and "Aliens" in " All the World is Birthday Cake " (S02, E05).

A subtle nod to the "Raiders of the Lost Ark" soundtrack can be heard once again as our intrepid team hack a path through the thick jungle canopy of Big Bear, California. Upon reaching a decaying structure of some sort, covered in thick, overgrown vines, Malloy taps an entry code into a keypad and MacFarlane gives us one of the funniest homages to "Return of the Jedi" ever.

Yaphit (Norm MacDonald) and LaMarr (J. Lee) parody a scene from "Return of The Jedi." (Image credit: Fox)

Yaphit (voiced by Norm MacDonald) suddenly thrusts forth through a small hole in a parody of the scene where C-3PO and R2-D2 approach the front of Jabba the Hutt's palace and are greeted by the TT-8L/Y7 gatekeeper droid. Bravo, MacFarlane, bravo.

Entry is granted to the resistance headquarters, which looks like a cross between the rebel control room on Yavin IV in "Star Wars" and the Starfleet headquarters in "Star Trek IV: The Voyage Home." Then we meet the resistance leader — a totally unexpected cameo from Lt. Alara Kitan (Halston Sage), who left the Orville and returned to her home planet of Xelaya for health reasons in the episode " Home " (S02, E03).

Kitan gives them a vial of beta-secretase protein, at which point the base comes under attack from the Kaylon. A tense firefight ensues between the resistance and a fleet of disembodied head drones, plus the scavenger ship in orbit above them has come under attack. Brave members of the resistance fall, one after another, as the battle on the ground seems hopeless. Eventually, they're overrun and the headquarters is destroyed in a massive explosion.

An army of Kaylon advance through the thick brush of the Southern California countryside to attack the resistance headquarters. (Image credit: Fox)

A Kaylon waiting inside the shuttlecraft to ambush our plucky heroes is quickly dispatched, and they speed off to rendezvous with the scavenger ship. However, that's still under attack, so with some trademark "madman" Malloy flying and an elastic-like maneuver with the tractor beam, the Union shuttlecraft is hurled into the landing bay. But they're not out of this yet. The quantum drive has been disabled so, in a scene reminiscent of "The Empire Strikes Back," Malloy leads the pursuing Kaylon into the asteroid field.

Mercer suggests that they hide in the nearby black hole — which is, of course, absurd. And if this show took itself too seriously, then it would, without a doubt, destroy any sense of realism. But, thankfully, it's water off a duck's back and perhaps aside from a rolling of the eyes, it's easy to concentrate more on being entertained than getting upset over the blatant disregard for any laws of physics.

While they patiently wait just inside the event horizon (they're invisible, you see, since not even light can escape — yeah, that's a 3 a.m. writers' room decision right there) time is passing more quickly for the Kaylon just beyond. They emerge, without being stretched to a subatomic breaking point , after the equivalent of two days and plot a course to Earth.

We learn that during the Battle of Earth, the Orville was disabled and crashed into the ocean. Grayson speculates that the snow-cone maker that sent her forward in time in the first place will be on board. Naturally, the ship is resting — still intact, thankfully — at the deepest point of the ocean, the Mariana Trench.

Meanwhile, with some time to kill on the way to Earth, LaMarr is busy deconstructing the dead Kaylon that was on the shuttle waiting to ambush them as they returned from the resistance HQ. He's attempting to access its memory and any useful tactical information, which turns out to be protected by quantum codes. However, LaMarr can access the Kaylon "Connecto" network, which is much like the link that the Borg have in "Star Trek." This will prove very useful a little later.

Ed Mercer (Seth MacFarlane) has never looked better, with his gritty, unshaven appearance and a more rugged attire. (Image credit: Fox)

During this time, Grayson and Mercer share a tender moment and talk about their future in this timeline and the future they're trying to return to. And then the ship arrives at Earth. We can see, even from orbit, that our poor little planet has been decimated; there are craters the size of small countries on the surface. Even the moon has been obliterated, looking like the one portrayed in the movie " Oblivion ."

There's no way the scavenger ship will survive the 7-mile trip straight down to the bottom of the Pacific Ocean to reach the Orville, but the Union shuttlecraft might. There's more great-looking VFX as the shuttlecraft makes its way through the depths … until they reach the derelict spacecraft. And it looks like someone left the lights on. Malloy detects a small energy signature and minimal life support on the ship. They're able to enter the shuttlebay and pressurize it before cautiously wandering through the dark, damaged corridors of the Orville.

At this point we hear another obvious musical nod, this time to the movie "Aliens," as a parallel is clearly being drawn to the tentative initial search of the deserted colony complex on LV-426 in that movie. Talla detects a life sign so they make their way to the bridge … and find Lt. Cmdr. Bortus (Peter Macon). He tells how the captain and first officer were killed during the battle with the Kaylon, so he remained onboard to pilot the ship long enough so that all the escape pods could be launched before it crashed into the sea. He's been surviving on combat rations and minimal life support ever since. Lest we forget that Moclans can eat just about anything.

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They hastily explain what's going on to Bortus along with the tragic news that the Kaylon have destroyed Moclus. LaMarr works to restore the Orville's main power and Mercer nervously takes the captain's chair. Plus, even more gorgeous VFX as they fly away from Earth accompanied by a powerful orchestral score that may or may not be a nod to " Star Trek III: The Search For Spock ." Who'd have thought we'd get to see the Orville breaching the surface of the ocean like a giant marine mammal?

Once in space, LaMarr begins working on setting the snow-cone maker/time-travel device only to discover that the information in the ship's computer is incomplete. Apparently, Isaac (Mark Jackson) never finished his calculations, and, regrettably, in this timeline he has been dismantled and is back on Kaylon, in pieces. LaMarr hits upon the idea that they look for the data on the Kaylon network — told you that would prove useful.

Mercer wanders down to the ship's mess and is joined by Grayson as he has a drink. The two have another meaningful moment before the time comes to go back in time.

In the briefing room, LaMarr explains that he can effectively locate Isaac's mind in the Kaylon network and download it to the body they have on board, allowing him to complete the calculations, activate the snow-cone maker and send Finn back in time to administer another mindwipe on Grayson. The only downside is that it will require every joule of energy on the ship, which means they have to be parked … and while he's connected to the Kaylon network, the enemy forces will be able to locate the Orville in space. So it's a race against time once they begin.

It doesn't take long for the Kaylon to find them and immediately reroute the nearest ships to intercept. Finn readies herself as LaMarr struggles with insufficient power, just like last week. Every system is diverted, including life support, as the Kaylon close in. Whatever happens, it's going to be close. Suddenly, the Orville explodes … and we cut to black.

But there's still 4.5 minutes left! We cut to Young Grayson, in her apartment, fast asleep in her bed. Her alarm goes off and she hauls herself out of bed — don't forget she's still hungover as hell at this point. Then, suddenly, she's gone. Then, suddenly, she's back … only now she's lying on the floor of her apartment, just as she was when she returned last week. Then Finn appears in the room and explains that the mindwipe didn't work.

"What's that?" asks Grayson.

"The future of the galaxy," Finn replies, and then she administers the beta-secretase injection.

Finn completes the procedure and then disappears as the timeline changes.

Grayson's phone rings … and it's Mercer … asking for a second date. To which Grayson smiles and agrees.

The end. Maybe?

While not as spectacularly badly balanced as the two-part season finale of " Star Trek: Discovery ," the second part of this two-part finale still feels overstuffed compared to the first. Perhaps MacFarlane just felt he needed to spend all of what was left in his VFX budget; shockingly, this might not be far from the truth."The Orville" has yet to be renewed for a third season, and who knows what affect the buyout of Fox by Disney will have. But if for inexplicable reason it isn't, then this was a great story to end on. Let's just hope that's not the case; it would truly be a travesty to end the show now.

This second season has been a marked improvement on the first, showing an almost exponential increase in the quality of writing. The first episode, " Ja'loja ," was exceptional, and while there have been one or two episodes that weren't up to the same standard, most haven't been far off. And then, of course, there was the Kaylon war. Wow.

It would be nice if the House of Mouse could confirm series three, so that we the fans can stop worrying and the writers can allocate some brain time to how it could unfold.

Season 2 of "The Orville" can be watched on demand on Fox Now and Hulu. It's also available on Fox.com in the U.S. In the U.K., it's on Thursdays at 9 p.m. GMT on Fox. The first season of "The Orville" is available to buy on DVD and a season pass can also be purchased from Amazon .