29 June, 1613: the spiteful and envious playwright Francis Pearson burns down the Globe Theatre during the premiere of Shakespeare’s final play, Henry VIII. Tormented with guilt, he drowns his sorrows at an inn, but the landlord beats him half to death and throws him out when he refuses to pay his bill. Outside, he sees the shadows moving in on him -- and is attacked and consumed by, quite literally, a demon from his past...

Over one and a half thousand years later, the TARDIS materialises in Europa, a fantastical recreation of Europe which was created after the fall of the Overcities, and stocked with demons from mythology and folklore. Europa is ruled by an offshoot of the Catholic Church based in a floating Vatican City, and the TARDIS has materialised in its Sistine Chapel. But the Doctor realises that the hidden face in the painting of St Benedict’s hand is not Michaelangelo’s face, as it should be; it’s something far stranger, and far more terrifying...

Historical and fictional characters live again in Europa in the form of Reprises, and some of them have formed an organisation called the Domino Order which opposes the oppressive rule of the Church. Pope Lucian, a would-be reformist, has invited the Dominoes Lord Byron, Casanova and the natural-born Miles Dashing to the Vatican to negotiate a truce, but Casanova is distracted by bedding his latest conquest and Dashing accidentally shows up for the rendezvous at St Peter’s Square instead of St Peter’s Basilica. Byron is thus the only one present at the meeting, and the only witness when a statue of the Archangel Michael comes to life and skewers the Pope. Byron flees, pursued by the Swiss Guards, who find and capture the Doctor and Sarah instead. They are sent to the dungeons of the Inquisition to face the Pit, a psychic vacuum where their greatest fear will be made manifest; however, Byron rescues them, and they flee together on his flying scooter, a Draco. The Doctor wins Byron’s respect when he outwits the smart-weapons pursuing them, enabling them to escape.

Dashing misses the excitement altogether and departs from the Vatican in search of Byron. Aiming for the Villa Diodati, Byron’s residence near Lake Geneva, he is blown off-course by angry Swiss gods and is forced to put down in Transylvania. Another of the three Byrons of Europa is located here -- but this one is a vampire, and although Dashing kills him, the vampiric Byron is reincarnated as a living moonshadow. Miles is forced to retreat from a mob of angry vampire peasants armed with stake-guns, and makes his way to Switzia, where he hires a new servant named Crocker (who is in fact much more intelligent than his master, but hides it for the sake of his pay). When night falls, the shadow-Byron pursues Miles, but not to kill him; it still retains enough of its nobility and dignity to answer the questions which Miles had posed to it during their battle. Some time ago, Miles was forced to kill his entire family when they were transformed into vampires, presumably due to the baleful influence of their rivals the Mindelmeres; ever since, he has sought an explanation for his father’s enigmatic last word, “Managra”. Byron’s shadow can speak only in riddles, but before it returns to Transylvania, Miles realises that it’s trying to communicate the concept of anagrams.

While searching for his missing colleagues, Miles inadvertently contacts the wrong Reprise of Casanova, who attempts to pass on the message to the proper Reprise, only to find him in bed with the other Casanova’s conquest. The two Casanovas duel over the error and one kills the other, but nobody watching is quite certain who won. The survivor then sets off to keep another forgotten appointment; Prince Ludwig of Bavaria had hired him for protection after allowing the forbidden play Twelfth Night to be performed at his castle. Casanova arrives only to find that the sinister Doctor Sperano and his Theatre of Transmogrification have already been and gone -- and in order to keep Ludwig silent, Sperano had removed his mouth, slicing open the blank flesh of his face when he wanted an answer. The devastated Ludwig tells Casanova of the play which Sperano’s troupe had performed, in which the Pope was killed by a living statue. Sperano had ordered Ludwig to forget what he had seen, but before leaving he killed Ludwig’s poodle as a final act of spite, and this unscripted act on his part enables Ludwig to remember everything -- including the fact that Sperano will next be performing in Verona. Casanova sets off to atone for his failure by killing Sperano.

Byron, Sarah and the Doctor spend the night in one of Europa’s Black Forests, where Byron explains more about the creation of Europa. The cabal of Concocters who created Europa used psychotronic engineering to populate it with ghosts, ghouls, werewolves, vampires and other creatures from folklore, apparently just to make it more interesting. Most of the population consists of the natural-born, but a historical archive called the Chronopticon, hidden somewhere in Europa, has also created clones known as Reprises, who usually appear as if from nowhere with all of the memories of the original. As well, Europa contains several different versions of its countries, from several different historical epochs, and in order to contain them all it’s larger than its surface area -- it’s dimensionally transcendental, which confirms the Doctor’s fears that it was created using Gallifreyan technology. When Byron describes the Theatre of Transmogrification, the Doctor notes that they perform only plays which he knows to have been written by Francis Pearson, a playwright so awful that every extant copy of his work was believed to have been burnt by angry villagers in the 17th century. His are the only plays to be performed in Europa; all other Elizabethan and Jacobean dramatists have been banned on pain of death. The Doctor reveals that Pearson was once involved in the evil ceremonies of Elizabeth Bathory, the Blood Countess, whom the Doctor once defeated at great cost -- and that after his own manuscripts were burned he set fire to Shakespeare’s Globe Theatre out of spite. Meanwhile, Doctor Sperano senses the presence of a gatecrasher in his drama, and to investigate, he kidnaps Sarah from beneath the Doctor’s and Byron’s noses. He places her under his mesmeric spell, renames her “Shara”, and questions her about the Doctor...

Following the Pope’s death the surviving Cardinals jockey for position, although Cardinals Richelieu and Torquemada are excluded under the “Nicodemus Principle” which forbids Reprises from becoming Pope. Moments after Lucian’s body is fired into space, however, he arrives at the meeting of the Conclave, apparently very much alive and claiming that the body was that of a clone. Cardinals Agostini and Maroc, apparently in the Pope’s confidence, accuse Cardinal Borgia of conspiring to murder the Pope and send him to the dungeons of the Inquisition, but he is “accidentally” crushed to death in the tunnels on his way there. Cardinal Francisco is also killed, by a mirror which explodes into shards after the image of Satan appears in it. Agostini is responsible for the deaths; he is in league with Sperano, who played the role of Lucian back from the dead in order to confuse the other Cardinals while Agostini arranged their deaths. Agostini bribes the Swiss Guards to murder Maroc, and thinks his position secure. But Richelieu intends to discredit him and overthrow the Nicodemus Principle, and to that end he has enlisted the help of Aleister Crowley and Doctor Faust, rivals for the position of Europa’s Official Antichrist. In exchange for their help, he promises to eliminate their common rival Paracelsus.

Unable to locate Sarah, the Doctor and Byron continue on to the Villa Diodati, where they meet Miles and Crocker, Mary Shelley, and the third of Europa’s Lord Byrons -- a version who has renamed himself Albé, and who spends his time in the Villa indulging his dark, sadistic desires. Faust also arrives, but before the meeting of the Dominoes can begin, Byron challenges Albé to a seance duel to determine who will survive to become the sole Byron of Europa. The Doctor catches Albé cheating, and interrupts the seance, knocking both Byrons unconscious; he then co-opts the power of the seance in order to get some answers. Miles’ father is summoned from beyond the grave, and Miles is appalled to learn that his family were in fact bloodthirsty criminals who couldn’t stand the sight of him. Rather than being rivals of the Mindelmere family, they were in league with them all along, until they stole Doctor Sperano’s magic pen and tried to use it to rewrite their own lives. Sperano stole it back, and took his revenge by rewriting them into vampires.

The Doctor reveals that Sperano is using mimesis, the art of living theatre, to alter the structure of reality -- and like “Managra”, an anagram of the word “anagram”, it comes from dark Gallifreyan mythology. Mary Shelley falls under Sperano’s influence and stabs the Doctor in the heart, but he survives due to his second heart, and when she recovers she heals him with a medicine from the Overcities. Byron and Albé recover and duel to the death with swords, and when Byron wins, this triggers a House of Usher mechanism which causes the entire Villa Diodati to sink into the mire. The Doctor and the Dominoes escape, and while Byron and Faust set off to attack Vatican City, the Doctor leads Miles and Mary to Brittania Gloriana, and the Globe Theatre, to find out what happened on the last night of Francis Pearson’s life.

Vatican agents are waiting for them at the Globe, but the Doctor recites the opening speech from Henry V, using mimesis to recreate the Battle of Agincourt. While doing so he realises that the Globe is a primitive TARDIS -- in fact, it is the legendary Chronopticon which creates Europa’s Reprises. He then recites lines from Henry VIII, the play being performed on the day Pearson burnt down the original Globe, and through mimesis he recreates the tragedy and is able to follow Pearson out of the burning theatre. Outside, he, Miles and Mary see a living darkness close in on Pearson and absorb him. The Doctor reveals that the darkness they saw was a Mimic, a creature which mindlessly copies whatever it encounters. Long ago, it was expelled from Gallifrey after absorbing much of the Time Lords’ technology; it eventually drifted to 16th-century Earth, where it became the echo of an infinitely more powerful and evil being which Elizabeth Bathory had summoned. The Doctor defeated that evil at great cost, but the Mimic remained, and it followed Bathory’s disciple Pearson to London, attracted by Pearson’s own lack of originality. Pearson and Managra merged to become the entity known as Persona, or Sperano -- a being capable only of rearranging that which it had already encountered, rather than creating anything new of its own. Persona is responsible for the creation of Europa, and for the past two centuries he’s been behind the scenes, setting up a stage on which to enact his dramas. Now that his work is done, he plans to enter the scene himself, on Thirteenth Night -- when the people of Europa will become the playthings of a dark creature echoing a petty man full of spite and hate.

The Doctor sends Mary and Miles to Verona to rescue Sarah from the Theatre, while he attempts to work out how to pilot the Globe Theatre. At Verona, they are reunited with Casanova, whose attempt to kill Persona fails due to Persona’s use of mimesis. They successfully rescue Sarah, and Miles is reunited with his former love Beatrice, whom Sperano had kidnapped and forced into his Theatre to avenge himself against Miles -- the sole Dashwood to escape his revenge. After seeing Beatrice to safety, Miles, Sarah, Mary and Casanova join Faust and Byron as they attack the Vatican. However, Faust betrays them to Richelieu, and they are surprised and attacked by Swiss Guards who kill Casanova. Under cover of the distraction, Crowley slips into Agostini’s chambers and frames him as a devil-worshipper. He then flees, only to find that Richelieu has betrayed him and removed his waiting Angelus so that Crowley, expecting a short drop onto a cloaked scooter, instead falls out of the floating Vatican to his death. Richelieu then calls off the Swiss Guards, explaining that he was co-operating with Mary Shelley all along; in return for her help in eliminating his rivals he will leave the Dominoes in peace, on condition that they do the same to Francia Bourbon. He allows Miles to throw Faust into the Pit for his treachery, so that the weak-willed Paracelsus will indeed become Official Antichrist. Meanwhile, Agostini is pursued by Swiss Guards, and tries to shelter in the TARDIS and drop it into the Pit to avoid capture -- but he is unable to close the doors, and the psychic vacuum pulls him out into the Pit, condemning him to face his worst fear of an eternity of torment in Hell. The TARDIS appears to be lost, but Sarah leaps into the Pit, faces down her own fears of abandonment and betrayal, triumphs over them, and recovers the TARDIS.

The Doctor pilots the Globe to Sperano’s final performance, where Persona is about to take on the role of Europa’s artistic director. Just as he is about to unmask himself to his audience, however, the entire Globe Theatre materialises onstage, interrupting his play. In the confusion, the Doctor drives the Theatre’s carriage, itself a primitive TARDIS, into the Globe. Persona pursues him into the Globe, but once he’s inside, the Doctor dematerialises the theatre, pilots it into the chaotic heart of the Vortex and uses mimesis to deprive Persona of his powers. Persona has been defeated by the use of original thought, something of which he is incapable. Following the Doctor’s instructions, Mary Shelley pilots the TARDIS into Persona’s carriage, and the Doctor escapes as the forces of the Vortex crush the interior dimensions of the carriage down to the same size as the exterior. Persona is crushed to death in the process, but he dies satisfied, knowing that in the end, he brought down the house.