The probe asks them how they plead, but Kryten informs the rest of the crew that this is just a formality, and that it'll kill them regardless of how or if they respond. In the lack of a better plan, they set course for GELF space, where the probe won't follow them. Before it gets there however, Starbug suffers crippling damage, and is forced to ditch in a lake on a moon occupied by the Kinitawowi, a tribe of ape-like GELFs. While the ship's automatic repair systems can deal with most of the damage, their oxygen generator is damaged beyond any hope of repair, and so the four go to meet with the Kinitawowi, who have a reputation for being comparatively friendly, along with being prolific traders. They are also skilled in rearing Emohawks, a smaller, domesticated version of the Polymorph previously encountered by the crew, which they use to steal emotions, apparently a valuable trading commodity.
Fortunately, the Kinitawowi have the required part, and are willing to trade for it. Unfortunately, their price is Lister staying on the moon and marrying the daughter of the tribe's chief. Once again lacking a better plan, the crew make Lister go through with the marriage and tell him to sneak out and return to Starbug in the night. Unfortunately, Lister is unable to even bring himself to do that, and flees from the village only minutes after his amorous bride starts making the moves on him. Lister's new father-in-law is naturally pretty smegged off by this, and sends his Emohawk after them to extract payment in the form of their emotions.
Despite the crew's usual caution and attention to detail, the Emohawk gets on-board Starbug. The Cat gets the scent of something unusual, but when he investigates the Emohawk ambushes him and sucks out all his cool, turning him into Duane Dibbley. Rimmer decides that a suspicious-looking gun must be the Emohawk and flushes it out into space, despite Duane trying to warn him that if he's wrong, he's flushing away their only weapon. Turns out Duane was right, and moments later Rimmer finds himself being Emohawk'd. He loses all his bitterness, and is left as Ace Rimmer.
Ace locks Lister and Kryten in the engine room and tells them that he and (unbeknownst to him) Duane are going to perform a Heroic Sacrifice and decompress the rest of the ship in order to kill the Emohawk. Fortunately, Lister and Kryten are able to stop Ace and work out an alternative plan to freeze the Emohawk, then extract and restore Rimmer and Cat's full personalities. They go looking for the creature, bemoaning how hard it is to actually find a shape-shifting creature, but quickly find a prime suspect when Duane suddenly finds himself with an extra Thermos flask.
The Emohawk has one last trick up its sleeve however; apparently it can transform itself into working machines and weapons, and so transforms itself into a hand grenade. Duane can only throw it six inches away, and so Ace throws himself upon the grenade, taking the blast. His hard light drive withstands the explosion, and Lister and Kryten freeze the Emohawk, saving the day. Ace requests to stay as he is for another 24 hours, but Duane is all too eager to become the Cat again. Unfortunately, it seems he'll have to wait a little longer, as he accidentally sprays the other three with the freezing gas.
- The Ace: The Trope Namer makes a comeback of sorts! Inverted with the Cat, who this time actually takes on Duane's full personality, and it's every bit as dorky as you'd imagine.
- All Crimes Are Equal: It's left ambiguous as to whether all crimes in deep space are punished by death, but Kryten implies that anything even remotely serious will get you blasted out of the stars.
- Anything but That!: "DUANE DIBLEY!"
- Baleful Polymorph: Played straight by Duane, who really isn't too pleased at his situation. Inverted by Ace, who really isn't relishing the thought of turning back to normal. And as far as we can tell, averted by the actual Polymorph.
- Bland-Name Product: The Emohawk ambushes the Cat by disguising itself as a can of "Beanz" baked beans.
- Captain Oblivious: Lister lectures the rest of the crew on how they have to be alert and watch out for the Emohawk... which is sitting atop Lister's head in its unmorphed form. Unfortunately, Lister's stood behind everyone else, so no-one notices.
- Cursed with Awesome: Rimmer prefers being Ace.
- Driven to Suicide: One way of interpreting why all of Ace's plans involve putting himself in mortal danger, especially since he openly admits that he doesn't want to become the original Rimmer again.
- Hot Guy, Ugly Wife: Not that Lister's a hunk by any stretch of the imagination, but he's still movie star hot compared to his GELF bride.
- I Hate Past Me: Ace openly refers to his normal self as a "maggot" among other such niceties. Inverted by Duane, who despite actually taking on his full personality (as opposed to "Back to Reality," where he still had the Cat's mind) isn't keen on staying that way for a moment longer than he has to.
- Insane Troll Logic: Rimmer's argument that the winning side in any war is the one with the shortest haircuts. He inadvertently disproves it himself during the episode, since the original, short-haired Rimmer disposes of their only weapon and then falls victim to the Emohawk, while the much longer-haired Ace is the one who ultimately saves the day.
- Jumping on a Grenade: Ace does this with the grenade Duane activates. He's able to walk away completely unscathed due to being a hard-light hologram.
- The Klutz: Duane Dibbley makes Jerry Lewis look like a master of hand-eye coordination, especially at the very end of the episode.Duane Dibbley: I can't throw! I throw like a geek!
- Leeroy Jenkins: This episode's incarnation of Ace comes across this way, as his plans generally aren't very well thought-out and always seem to involve him doing a Heroic Sacrifice. This is likely due to Rimmer getting all his bitterness sucked out, but still not having the intelligence and training that the original Ace has.
- Mercy Kill: Ace's "plan" for dealing with the Emohawk is to snap the Cat's neck.
- Noodle Incident: When Lister is trying to avoid getting marrying a GELF bride so the crew can get a part for the Starbug. Rimmer tries to convince him to go marry the yeti creature because "you've dated worse." Lister angrily retorts "Only due to bad disco lighting!"
- Not Helping Your Case: Lister argues that they don't steal from derelicts, they just blast their way in and swipe what they need.Rimmer: Lister, if this goes to court, I demand separate lawyers.
- Rule of Funny: Sucking out the Cat's élan shouldn't really cause him to develop buck-teeth and a mop-top, nor should Rimmer losing his bitterness make his hair instantly grow out. But then we wouldn't have Duane Dibley and Ace Rimmer again.
- Screw This, I'm Outta Here!: In exchange for parts for Starbug, Lister must marry one of the GELF's daughters. Initially intending to flee into the night while the GELF bride is asleep, it turns out that the GELF bride wants to consumate their marriage that night... and won't take no for an answer."Just gotta slip into something a little bit more comfortable. It's called Starbug."(As the rest of the crew head back to the shuttle, Lister runs to them.)"CHANGE OF PLAN! LEG IT!"(They follow suit)
- Script-Reading Doors: The airlock starts to open as Ace is reaching for the controls.
- Self-Deprecation: A rare example of this from Rimmer, who in the opening scene openly admits that he gets pleasure in enforcing the Space Corps Directives in the most anal-retentive ways possible.
- Sequel Episode: To "Polymorph", as well as "Dimension Jump" and "Back to Reality".
- Sequel: The Original Title: Was originally going to be called Polymorph II: Emohawk but Doug Naylor thought this sounded too much like a football score.
- Status Quo Is God: While it's completely understandable why the Cat wouldn't want to stay as the Duke of Dork, there's no reason given for why Ace has to (or would want to) turn back into the original Rimmer. Granted, this Ace has a tendency towards putting himself in danger, but considering his hard light status that's really not as big of a risk as it might be.
- Take That, Audience!: Duke of Dork Duane Dibbley is described by Ace Rimmer as "Looking so geeky I don't think he could get into a science fiction convention".
- *Twang* Hello: Almost subverted: from a GELF, an arrow twanging into a tree (and not into you) is really considered a very warm greeting.
- Verbal Backspace: Kryten is forced to do this with Lister's guitar after they crashed. Seeing as how Lister wasn't there at the time, he probably told himself that as an alibi for himself.Kryten: Well, at least Mr Lister's guitar survived intact. (The Cat grabs it and smashes it against the floor, handing the pieces back to Kryten) ...Not even Mr Lister's guitar survived intact.
- Yank the Dog's Chain: An episode after Starbug is massively improved by the simulants, their ship is blasted out of the sky and trashed.