Robotech II: The Sentinels was an attempt to produce original content and a sequel series after the end of Robotech. Harmony Gold USA worked with Tatsunoko Productions in producing the show, but only three episodes were worked on before the rest was cancelled because of the crash of the Dollar to Yen exchange rate in the 1980s, which forced Matchbox to back out as a sponsor. Since HG was not able to finance the show's production, it was decided to make it a feature film instead, which was released initially on September 1988, followed by Streamline Pictures later released it in 1992. A remastered version was recently released with the Robotech: The Complete Set collection in 2011 and in 2013 from Lionsgate, showing the first three animated episodes as originally intended.
The Sentinels takes place in 2022, with Rick and Lisa about to be married as the Robotech Expeditionary Force (REF), known publicly as the Pioneer Expedition, prepares to leave Earth behind to search for the Robotech Masters' homeworld Tirol, hoping to stop a future war in its tracks. Instead, the SDF-3 would be left stranded and forced to work with both the Tirolians left behind by the Masters, and a ragtag group of alien resistance fighters, the Sentinels, to defeat the Invid Regent. If they can't succeed in time, the United Earth Government left behind would be left helpless before both the Robotech Masters and the Invid Regess, who have set their sights for humanity's homeworld.
Due to the show being canned, the bulk of the story was told through various adaptations, based on the scripts and technical notes provided by Harmony Gold. The one adaptation that reached completion was the novelization written by Jack McKinneynote , published in 1988 after the adaptations of the original series. A comic book adaptation of the story published by Eternity Comics (an imprint of Malibu Comics), and later by indie publisher Academy Comics, ran from 1988 through 1996, but was cancelled short of completion.
However in 2005, HG had announced that the Sentinels saga and all other existing expanded universe material was being retconned in favor of Robotech: The Shadow Chronicles and its spinoffs. For what it's worth, the prequel comic Robotech: Prelude to the Shadow Chronicles connected the Broad Strokes of established Sentinels events to the Shadow Chronicles arc, even starting with a flashback to a key event from the last Academy issue published.
The proposed show provides examples of:
- Amazonian Beauty: Bela and Gnea, two of the Sentinels leaders who are members of a Proud Warrior Race from the Lady Land planet Praxis. Both of them, and the other Praxians, are very tall, strong, and distractingly beautiful to many of the male humans.
- Animation Bump: The sections of the Sentinels movie set on Tirol are better drawn and rendered than the sections on or around Earth. This is because they are the earliest footage, from back when the Japanese animation team was allowed creative control over the story. Carl Macek believed that the lead director was intending to repurpose the footage as an independent series (the original story centered on Rem, Jack and Karen) for release in Japan. Macek started by having extremely detailed scripts for every episode written by himself or Ardwright Chamberlain, neither of whom had any experience writing or directing original animation. The lackluster scripts, in addition to a pissed-off animation crew and a lessened Yen to USD ratio, lead to the subpar animation that followed.
- Ascend to a Higher Plane of Existence:
- Postscript Novel for both the original McKinney novelizations and the Sentinels adaptation, the heroes realize that Haydon, the Precursor who had uplifted and shaped the Invid along with each of the alien species from Sentinels, was waiting for one of them to ascend — in order to follow in their footsteps, no matter what happened to the original universe in the process. Ironically, the Regess admits that even after becoming the Genius Loci of "newspace", all she really wanted was to return to her species' original form from before Zor's arrival. In The End of the Circle, a
- Also in End of the Circle, Doctor Lang makes his own attempt to ascend, in a way that would sacrifice his existence as a sapient being, in order to somehow tip the scales of fate so the SDF-3 and the main characters could survive the clash between the Regess and Haydon.
- Attack Its Weakpoint:
- In the Sentinels novels, Breetai is proud of how the Zentraedi have fixed the design flaw in their battle pods from the Macross saga, something his culture was psychologically incapable of doing before.
- Attack of the 50-Foot Whatever: In the Sentinels novels, when the occupying Invid finally cross the line with the Haydonites and Haydon IV's central consciousness retaliates, it creates an army of avatars shaped like Zor, with special mention going to a giant sized Zor imitation that attacks the Regent's ship!
- Back for the Dead: Lynn Kyle in the Sentinels. He reappears at a crucial moment to save Minmei, and is shot dead by T.R. Edwards. It was not intended to be this arbitrary, since Kyle was supposed to appear as a mysterious character in the background throughout the series before suddenly revealing himself when he tried to save Minmei, but the authors of the novelization only included a few previous appearances, and there is no implication that he's anyone other than a normal bartender or a random REF soldier. (He's the one who switches on the intercom and broadcasts Minmei's lonely rendition of "We Will Win" at the bar piano as the Sentinels leave the Tirol system; he also signs a few Epigraphs using his REF serial number instead of using any name.) This is similar to how Sue Graham and young Scott Bernard were supposed to be recurring characters, but only appeared once or twice in inconsequential roles.
- Belligerent Sexual Tension: Jack Baker and Karen Penn , especially in the Jack McKinney novels. It was meant to be a counterpart of Rick and Lisa's initial arc.
- Big Guy Fatality Syndrome: In The Sentinels, Breetai activates a Self-Destruct Mechanism to take down the Invid Regent.
- Canon Foreigner: Most of the cast of The Sentinels, in an effort to give the show original content.
- Combining Mecha: The Sentinels had the titular alien Resistance fighters arrive in the Farrago, a combination of ships from each of their member species created as a trophy for the Invid Regent. The original ships are able to separate and recombine. When Rick Hunter organizes a group of humans to join, they add a REF-issue Base on Wheels as their contribution to the ship.
- Downer Ending: The End Of The Circle picks up at the same point as Shadow Chronicles, but proceeds with wildly varying, yet completely different tones, ranging from Downer (Sera wastes away without the Regis, and Ariel/Marlene is next for most of the book) to just plain stone cold stupid ( After a variety of weirdness including the main characters' kids summoning the SDF-1's missing fold drive by chanting "Ro-Bo-Tech", Minmei is stranded in a pocket universe with Rem — a Sentinels character who was another clone of Zor — and pregnant with Rem's child, who is somehow going to actually be the original Zor, bringing time loops into everything at the last minute.)
- Higher Understanding Through Drugs: The Hat of the Garudans (fox people). Their homeworld's atmosphere is a mixture of chemicals and microorganisms that drive most other species to madness if they breathe it; Garudans have evolved (with the help of the Precursor Haydon) into a symbiosis that allows them a virtually mystic awareness bordering on full-fledged Psychic Powers. During the last battle against T.R. Edwards in the Sentinels novels, Rick and Lisa are forced to take a few controlled breaths of Garudan air in order to avoid the dangers of the Invid hive on Optera.
- Jerkass Has a Point: The Sentinels has another instance at the press conference before the launch of the Pioneer Mission and the Robotech Expeditionary Force with the heavily armed SDF-3 to try and reach a compromise with the Robotech Masters before they attack Earth. When Exedore explains that the Pioneer Mission includes so many heavily armed warships in spite of being a diplomatic mission is because they don't know how the Masters will react and there are no apparent threats to Earth anyway, Leonard jumps up and starts screaming apocalyptic predictions that come to pass exactly: he's not so optimistic about the lack of an enemy threat, and as the watchers already know the Masters are already coming to Earth (also making the Pioneer mission useless), and that's without Tesla, The Dragon to the Invid Regent, suggesting to track down Zor's ship (the Regent refuses because he hates the Masters too much to abandon the attack on Tirol, but that could have been another threat to Earth), or the Regess deploying the Sensor Nebula to track down the Flower of Life (and that is another threat to Earth); he declares that "the departure of the SDF-3 and its weapon systems will make Earth hopelessly vulnerable to attack!", and the Masters' motherships have Deflector Shields that make them heavily resistant to anything less than the Reflex Cannons mounted exclusively on the SDF-3 and some of her escorts, and it's only the return of two waves of REF ships that give the Southern Cross the firepower to score a Pyrrhic Victory; he shouts that in case of attack the Robotech Expeditionary Force will be at the other side of the galaxy , and when the Masters arrive the REF is in fact going in that direction. He's so right, and being a jerk about it, it's almost painful to watch...
- Made a Slave: The origin of the original Sentinels; they were aliens from the "Local Group" near Tirol and Optera held captive aboard the Farrago to become trophies for the Invid Regent, until they managed to stage a rebellion. Once free, they swore to fight until their worlds were free or they were dead.
- Myth Arc: Each of the homeworlds of the Sentinels had been touched by the precursor known as "Haydon" in one way or another; and before sending the SDF-1 to Earth, Zor followed in Haydon's footprints attempting to seed the Flower of Life on each world. Cabell, Rem, and Janice search for knowledge about Haydon on each Sentinel world, while the Invid scientist Tesla tries to use the unique Flowers from each world to fuel his Goal-Oriented Evolution.
- One-Gender Race: The Praxians. Deconstructed as they require artificial means to reproduce, ironically making them like the original Japanese anime's 'Proto Culture' that turned to cloning and discarded sexual reproduction completely, leading to a mutual war of extermination between men and women.
- Phlebotinum-Handling Requirements: In the Novelizations and comic adaptations of Sentinels, the alien Karbarran race has a unique bond with the "Sekiton" peat moss, descended from the Invid Flower Of Life, on their homeworld. Sekiton can be burned to produce enough energy to power interstellar starships — but only if it's physically handled by a Karbarran. If not, it remains so inert that it can't even be lit on fire. This gets used as an excuse for Phlebotinum-Induced Steampunk.
- Plot Hole:
- In the novelizations, the Invid Regent and Breetai die in single-combat in the skies over Optera. This was invented for the novelizations; in the TV series the Regent died much earlier at T.R. Edwards' hands, who proceeded to crawl into his exoskeleton and take control of the Invid. Daley and Luceno chose to have him die in a more fitting way, and give Breetai (who hadn't been doing much in the TV series) a heroic death. The trouble is that the novels also had Breetai returned to giant size so he could lead a contingent of Zentraedi to mine monopole ore on Fantoma. The Regent is only about 15 feet tall, Breetai should have been able to squash him in his hand, like John Goodman did to that frog in O Brother, Where Art Thou?. (The cover artist seems to have seen this problem, and has the micronized Breetai on the cover of Rubicon.)
- Why do the Invid launch an all out on attack on Tiresia, which it's made very clear that they've already occupied the city? It's because the footage was edited out of order in the compilation movie. Originally it happened like this: the Invid folded in, launched an attack on Tiresia only to be repulsed by the Bioroids (if you watch carefully you'll notice there's no clear victor in the battle footage). The Regent switched tactics and sent in the Inorganics, which is how they took over the planet. This also explains the origin of the damaged Enforcer that Rem uses to disable the Hellcat that has Cabell pinned down.
- Pragmatic Villain: While The Sentinels shows the Pollinators are not immune to captivity, in the Southern Cross novelization the Robotech Masters know that trying to simply shoot Polly is a waste of their now very precious time.
- Sequel Hook: Being made of the completed episodes of what should have been a whole series, has the indications the Tirolians and the Robotech Expeditionary Force will both fight the Regent's faction of the Invid and the Regess announcing her intention to deploy the Sensor Nebula, that will show up in "The Masters" and lead to her coming to Earth.
- Spear Counterpart: The Sentinels introduced the estranged mate of the Invid Regess, the Invid Regent, who was planned as the Big Bad of the series.
- Tie In Novels: Jack McKinney's adaptation of the unproduced Sentinels sequel, and several other original stories.
- Villain World: Earth between the departure of the Sentinels and the final battle of the Second Robotech War, as it was effectively in the hand of Anatole Leonard, former member of the Anti-Unification League.
- You Don't Look Like You: In The Sentinels Exedore and Breetai look nothing like their Macross Saga counterparts (though with Breetai it's more difficult to tell because he wears a Judge Dredd-like helmet which leaves only his mouth and chin exposed). Sketches included with the scriptbooks indicate that they started out as completely different characters (since Harmony Gold didn't have the right to the likenesses of any of the Macross characters), who just happened to fill the exact roles that Exedore and Breetai should have played. Carl Macek ended the insanity when he wrote the scripts and turned them into Exedore and Breetai. The novelization explains that Exedore got cosmetic surgery when he had to start taking a more political role which would involve speaking in public.