This was the first Big Finish episode to feature the shape-shifting companion Frobisher, from the Doctor Who Magazine comics. It's also Steven Moffat's favourite Sixth Doctor episode in all of Doctor Who, and it was a clear influence on his own "Heaven Sent".
Frobisher, the shapeshifting penguin detective, has convinced the TARDIS to create semi-living fish for him to toy with. The Sixth Doctor tries to explain that even semi-living things can feel pain and distress, but Frobisher won't listen until the TARDIS herself can't cope with Frobisher's games anymore and shuts down entirely. She parks the Doctor and Frobisher inside a medieval-style castle, where the new god-king is about to be crowned.
The World of Snark is inhabited by people whose entire lives revolve around rituals. The old king had ritualistically married his pretty wife, ritualistically conceived a do-good son and grown to ritualistically deeply hate him. The queen had ritualistically slept with the captain of the guard, who was then ritualistically executed for fathering the ritualistic bastard son. This son, the new king's ritualistically evil half-brother, plans to depose his brother now that the old king has died. An old scribe notes down every moment of the king's life, gathering each new Bible in the library. Well, sort of a library. Well, his bedroom.
Upon arriving in the middle of the ceremony, the Doctor and Frobisher are instantly mistaken for the Holy Big Talking Monochromatic Bird and his companion who brings with him every colour of the rainbow. The new king, who's really very confused about the whole deal, becomes even more confused when the coronation fails to give him actual god-like powers. He's too nice of a chap to pretend he's divine, so he promptly abdicates and tells the people to assassinate him for blasphemy. They won't listen, though, and he's forced to accept his new role. The new king's wife begins with the ritualistic torturing and mocking of the old queen (who's not in the mood), while the high priest goes off to ritualistically conspire against the new king together with the evil half-brother.
While Frobisher stays with the king (after observing the ritualistic assassination attempt), the Doctor soon finds out that the old scribe's books are all written in the same handwriting. Even the ones dating back to previous dynasties. What's more, each king's life ends exactly on the final line of the final page of each book.
The king decides that he really, really, really doesn't want to do any of this, so he makes Frobisher the new god-king instead. This does not go over well with Frobisher.
Meanwhile, the evil half-brother has a secret that's decidedly not tradition. He has a child, a young boy who's been kept alive for five years in the castle's deepest dungeons. The child was raised "pure", without language — even his mother's tongue had been cut out during his birth. The child turns out to be a malicious God, intent on killing everyone it encounters. The Doctor is an unexpected factor in its plans, but — as the child finds out — isn't immune to Mind Rape. After violating the Doctor's memories, it goes off into the castle and starts murdering everything it can find... asking "are you my father?".
In the end, it turns out that the evil half-brother wasn't the child's father after all. It was the old scribe, whose punishment this prison pocket-world revolves around. The old man had once killed his own son, and had created the fantasy of kings hating their sons and princes becoming god-kings as a coping mechanism. He had already lived the story many times over, in a continuous loop, always ending with the child's murderous rampage. When the TARDIS' dimensional stabiliser became damaged by Frobisher forcing her to create semi-living lifeforms, she had fled to the nearest dimensionally transcendental space going through the same kind of thing, in order to repair herself with its data. The scribe confronts his child for the final time, and ends the "Groundhog Day" Loop by commiting Heroic Suicide.
The Doctor tries to pretend that none of it mattered, since none of it was real, but Frobisher reminds him that even sort-of-living things count.
Frobisher: No, Doc — that's no consolation. They thought they were real, didn't they?
The Doctor: Just like the fish in the swimming pool... they felt pain, they felt fear... and more than that, they had hopes, and dreams and families. Yes. It is terrible. But that's what comes of travelling in the TARDIS. All the people you meet, all the planets you see: you know they won't last forever. And our next journey could be to a time when they'll all have been long forgotten. Such little lives... that we could feel like gods, set apart from them all.
Frobisher: And... that's supposed to make me feel better?
The Doctor: No. No, not at all.
Frobisher: For a while back there, Doc... I actually felt I could do some good! I actually felt I could save them all.
The Doctor: I know, Frobisher. Believe me... I know.
The Holy Terror provides examples of:
- Absurdism: Capital-A Absurd black comedy is par for the course with Robert Shearman episodes.
- Abdicate the Throne: Pepin's plan, but the "story" is trying to force him not to.
- Adipose Rex: The former empress, Berengaria.
- Anyone Can Die: Livilla, Arnulf, Childeric, Pepin and Berengaria are all killed off over the course of the story, in that order. The trope is then taken up to eleven in the final part, where its revealed that the entire castle is ficticious, created by Eugene's imagination, and even he is killed by The Child in the end, leaving only The Doctor, Frobisher and the empty void.
- Bastard Bastard: Childeric, although he's not evil enough in Berengaria's eyes. She's very, very wrong.
- Big Bad: Eugene is this for the story, as he is the one who created the Castle as his Self-Inflicted Hell, killed his son in the first place, inflicting the emotional damage which will turn the Child into the killing machine he is, and though he is given the chance to pull a Heel–Face Turn at the end, he kills himself by way of the Child instead.
- Big Bad Wannabe:
- Clovis, as described by the Doctor in the fourth part.
- Childeric too, in a way, who is killed by his own creation, the Child.
- Blatant Lies: The Sixth Doctor: "The TARDIS, like her master, has her ego under control."
- Break the Comedian: Frobisher starts getting serious for a change when he finds himself being crowned Emperor of the Castle, even doing his best to introduce the people to the concept of free will... only for it all to go horribly wrong when the Child appears and begins massacring the population. Frobisher is deeply shell-shocked by the event and can't muster up a single joke in the epilogue.
- Buffy Speak: Frobisher is nearly constantly referred to as "the big talking bird", which makes the line "All hail the big talking bird!" quite funny.
- Burn the Witch!: When a new God-Emperor is crowned, all those who worshipped the old one are burned at the stake. Although they are given a chance to recant, which most of them take.
- Call-Back: To "then you won't feel the bullets when we shoot you".
- Cliffhanger: Three, as usual, but most notably Part Three's cliffhanger is especially shocking: The Child's voice morphs into that of Eugene's as he asks who his father is.
- Continuity Nod: The Sixth Doctor is still opposed to fishing.
- Corrupt Church: And how! The High Priesthood has a long history of betraying the true monarch to the evil brother going back to time immemorial. It's traditional!
- Creepy Basement: With a Creepy Child in it.
- Death Seeker: Berengaria, Pepin and Childeric's mother, is this. She is eventually killed moments after finally seeing her son in a new light, and just after said son was murdered in front of her eyes by the Child.
- Designated Villain: In-Universe even: The High Priest and the bastard brother. Not only Childeric but everybody before them in the Generation Xerox.
- Dirty Coward: Clovis despite the fact he was trying to gear up for a Heroic Sacrifice in contrast with his nature.
- Doom Magnet: The TARDIS' tendency to do this gets lampshaded.
- Downer Ending: Big time. It's a Dream Apocalypse, which only the Doctor and Frobisher, since they do not belong in the dreamworld, survives.
- Dying Vocal Change: With Eugene dead, the Child's purpose is complete, and as a result ceases to exist; as he does so, his voice gradually ages until it's identical to Eugene's again, then fades away entirely.
- Egopolis: As soon as a new emperor is crowned, his people convert all the old statues into images of him.
- Enfante Terrible/Reality Warper: Childeric is trying to groom his son into one. Well, Eugene's son. And it works far too well.
- Epiphanic Prison: Is this for Eugene.
- Evil High Priest: As is designated by tradition, the High Priest must always betray the Lord Emperor. Clovis, however, doesn't enjoy playing the role.
- Evil Plan: The bastard son is obligated to have one for the rebellion, but Childeric's plan is much more evil than the Castle has ever seen before.
- Eye Scream: If you don't pledge your allegiance to the latest God Emperor one eye is gouged out so you can watch yourself be burned at the stake.
- Faux Affably Evil: Childeric
- Fisher King: Eugene has this effect on the reality.
- Generation Xerox: Invoked. Every generation has the abusive royal parents, a milquetoast heir, a Bastard Bastard who conspires with the High Priest to overthrow the heir, etc. It's the key to the truth about the place.
- A God Am I: Played with, Frobisher is worshiped as being some sort of an angelic being ("All hail Frobisher! All hail the big talking bird!"). He is not comfortable with it at all. Also, the King is traditionally worshiped as a living God. This leads to problems, since each King invariably commits the ultimate blasphemy by dying.
- God-Emperor: Though they're not really immortal.
- Goo-Goo-Godlike: The Child is a Humanoid Abomination who was raised to be a Physical God. The experiment was a complete success.
- The Grotesque: Childeric, Pepin's evil brother who plots to overthrow him. He appears to be the villain of this story, but he really isn't.
- "Groundhog Day" Loop: Unbeknownst to Eugene until the Weirdness Censor shatters.
- Heroic Sacrifice: The Captain of the guard for the people, although it's more of a Stupid Sacrifice, since the assassination attempt is always carried out with blanks instead of bullets, at least until they take the Doctor's advice.
- Senseless Sacrifice: Pepin does this for his mother, and is killed by the Child. Depressingly, Berengaria is killed anyway.
- Humanoid Abomination: The Child is revealed to be a force of nature designed to serve as a Reset Button and complete Eugene's Self-Inflicted Hell.
- Hoist by His Own Petard: Childeric is killed by the Child when he is unable to keep him under control.
- Insane Troll Logic: As an emperor, Pepin is supposedly invincible so the ritual assassination attempt is done with blanks because it wouldn't work anyway.
- Invincible Boogeymen: The Child. Nothing in the castle can kill it or even slow it down; the Doctor can't fight it, dissuade it or technobabble it away. By the end of the story, the heroes are reduced to hiding in the throne room while the Child massacres its way through the populace, knowing that there's nothing they can do but wait until it comes after them.
- Irony: Scribes are not important? They most certainly are.
- Journey to the Center of the Mind: Beginning the moment The Doctor and Frobisher step out of the TARDIS.
- Lady Macbeth: Livilla, Pepin's wife. She tries to be this for Childeric.
- Last Words: The Child restores Arnulf's voice only to hear his before he kills him.
- Luke, I Am Your Father: Subverted, and then played straight: Childeric isn't the Child's father, but Eugene is.
- Madwoman in the Attic: Childeric's son in the vault
- Mind Probe
- Mind Rape: What's actually going on. The entire castle serves as Eugene's punishment for the murder of his own infant child. The Child also does this to The Doctor at one point.
- Meaningful Name/Punny Name: Childeric.
- Merlin Sickness: Forced on Levilla.
- Mood Whiplash: One of the most well-loved examples in Big Finish. The serial switches from a hilarious parody of stereotypical Shakespearean tragedy and suddenly becomes a disturbing examination of destiny as the characters stare inevitable death in the face and a man's fractured mind is slowly torn apart before the Doctor and Frobisher's eyes.
- It's made even worse, as after the melancholy ending, we hear the ending theme followed immediately by chantings of "All hail Frobisher, all hail the big talking bird!" to a techno beat.
- Mundane Made Awesome: Each God-King has to perform a miracle during their coronation. By the time the Doctor arrives, it's been pared down to a (rigged) card trick.High Priest: Now, your Majesty. Is it by any chance... THE THREE OF CLUBS?!!
- My God, What Have I Done?: At the end of the story, Eugene experiences this when he remembers that he killed his son.
- Narrator: The scribe is this in-universe for the bibles.
- Nightmare of Normality: Eugene's current state of being, having forgotten all about his power over the Castle and settled into the mundane life of a scribe.
- Obliviously Superpowered: The seemingly unimportant scribe Eugene Tacitus is actually an immortal Reality Warper and the Castle is his creation. However, due to a combination of Obsessively Normal tendencies and being trapped in the Castle for eons, he's completely forgotten his powers... even though he's still unconsciously steering the entire course of history. He's not even aware that he's immortal, assuming that he's just the latest member of his family to become the court scribe.
- Offing the Offspring: Eugene's crime and the reason why he has been placed in the castle.
- Pocket Dimension: The Castle itself is one.
- Precision F-Strike: Alright, you evil old bitch!.
- Prison Changes People: Eugene was changed so much by his time imprisoned that he can't even remember who he really is - or was.
- Psychological Torment Zone/Self-Inflicted Hell: The Castle is this for Eugene, who is stuck in it forever because of his own deeds, namely murdering his son.
- Reality Warper: The Child is capable of warping reality within the Castle at will; as it turns out, so is Eugene - to the point that he usually recreates the Castle from the featureless void that the Child renders it down to.
- Relieved Failure: Berengaria barely raises an eyebrow at her fall from grace, actually demanding to be taken to a cell. As it turns out, she's been bored senseless with the imperial lifestyle and is very eager to experience the imprisonment, torture and ritual execution that will ensue now that she is no longer a goddess - eventually becoming a Death Seeker and resisting all efforts at saving her life.
- Royal Bastard: One of the rituals in this episode is that the Queen always has two sons: one legitimate, one a deformed and evil bastard who will conspire to overthrow the heir.
- Shapeshifting Sound: Frobisher's one instance of shapeshifting - in which he mesomorphs a different-shaped beak in order to match a poorly-made statue of himself so the sculptor won't be executed for failure - is accompanied by a rubbery squeaking noise vaguely reminiscent of a balloon animal being shaped.
- Shout-Out: When Pepin addresses his people, it seems very much like Monty Python's Life of Brian.
- Talking Animal: Frobisher, the big talking bird.
- Theme Naming: Characters are named after French or Roman royals famous for scheming and backstabbing. Tacitus is named after the general and historian of the same era as the Roman namesakes.
- The Thermidor: God-King, bastard brother, corrupt High Priest. Lather, rinse, repeat.
- There Are No Coincidences: All of the bibles end exactly on the last page. Strangely enough, Pepin's seems to be very thin.
- Tongue Trauma: Childeric does this in order to mute his servant, and almost to Eugene.
- Too Kinky to Torture: The former empress says back in her day they REALLY knew how to torture.
- The Un-Favourite: Pepin is this to his mother, not that Childeric is any better in her eyes.
- Wham Line:The Child/Eugene: Are you my father?
- World Limited to the Plot: Because the "plot" really is everything to this world.
- Your Head Asplode: The Enfante Terrible's rampage during the climax, complete with an incredibly disturbing tearing sound.
- Your Worst Memory: The entire castle has been set up to force Eugene though a replay of the crime he was imprisoned for, making him relive the murder of his son in "every horrific detail."
"Are you my father?"