S7E20
Tragic
Written by Don Houghton
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Inferno Part 2

As Professor Stahlman accelerates a dangerous drilling project despite warnings, the Doctor investigates a series of violent deaths linked to a mysterious green liquid and a terrifying retrogressive transformation, risking everything to prevent a catastrophic volcanic eruption.

Episode Two opens with escalating tension at the Inferno project, a facility drilling deep into the Earth's crust. The Doctor and UNIT investigate strange occurrences surrounding the project. A soldier named Slocum is exposed to an unknown energy source turning him into a violent beast-like creature before he dies, exhibiting unnatural strength and heat. Simultaneously, the project's director, Professor Stahlman, pushes forward with the operation, dismissing concerns about the safety and stability of the nuclear reactor providing power.

As the Doctor investigates Slocum's death and a similar incident involving a technician, he uncovers a connection to the Krakatoa volcanic eruption. He attempts to warn Stahlman about the dangers, but the Professor, driven by ambition and a belief in his own superior knowledge, ignores him. Key personnel Gold and Petra slowly begin to worry at Stahlman's hubris, while deaths continue to pile up which the Brigadier and UNIT are increasingly concerned about.

Stahlman's recklessness leads to a power surge at the nuclear reactor which almost causes catastrophe. The Doctor intervenes, manually resetting the power levels after Stahlman refuses to acknowledge the problem. Greg Sutton, a technician working at the drill head, expresses concern about the lack of safety precautions, but Stahlman dismisses his worries.

The Doctor and Liz Shaw discover a mysterious green liquid leaking from the drill, which defies analysis and emits intense heat. The computer warns of an impending catastrophe if drilling continues, but Stahlman disregards the warning, sabotaging the computer by removing a micro-circuit. The Doctor confronts Stahlman, but Stahlman continues with his plan to accelerate the drilling process, and by handling the green substance his hand begins to turn green.

As the episode reaches its climax, Stahlman orders an acceleration of the drilling rate, ignoring all warnings. The Doctor realizes that Stahlman's actions are leading to a volcanic eruption threatening to destroy the world. The Doctor knows he will have to take drastic action to stop Stahlman and prevent disaster.


Events in This Episode

The narrative beats that drive the story

25
Act 1

The episode opens in the tense aftermath of a violent incident at the nuclear reactor, where the Doctor confronts a transformed and aggressive Slocum. Despite Slocum's unnatural resilience, Wyatt's shots eventually bring him down. The Doctor, observing the red-hot power lever, manually resets the dangerously high power levels, averting a potential meltdown. Professor Stahlman, however, dismisses the near-catastrophe as mere "incompetence" from the reactor staff, steadfastly refusing to acknowledge any systemic fault within his drilling operation. This unwavering arrogance immediately establishes his dangerous hubris. Meanwhile, technician Greg Sutton expresses growing safety concerns to Petra, hoping to influence Stahlman through her, highlighting the internal dissent brewing within the project. The Doctor's subsequent investigation of Slocum's body reveals disturbing details: abnormal strength, intense radiating heat, and a process he terms "retrogression of the body cells," where the victim appears to be reverting to an animalistic state. This leads to a profound and alarming connection to the 1883 Krakatoa volcanic eruption, suggesting a historical and geological link to the current crisis. The danger escalates further when Wyatt, exhibiting similar green-faced symptoms and violent behavior, disappears and later dies after a desperate chase and confrontation with the Doctor. This second fatality, mirroring Slocum's transformation, solidifies the terrifying reality of the spreading affliction and its potential link to the deep Earth drilling.

Act 2

Driven by an unyielding ambition and a dismissive attitude towards any perceived obstacles, Professor Stahlman announces his intention to accelerate the drilling speed by an additional twelve percent, brushing aside Petra's hesitant expressions of concern regarding safety. This decision underscores his escalating recklessness. Concurrently, project personnel make a troubling discovery: a mysterious, intensely hot green liquid is now leaking from the drill's output pipe. This anomalous substance defies all attempts at scientific analysis, further deepening the enigma surrounding the project. The Doctor, upon observing the liquid, immediately reinforces his earlier hypothesis by linking it directly to the Krakatoa eruption, cementing the connection between the drilling, the strange transformations, and a catastrophic geological event. The Brigadier, gravely concerned by the mounting body count—three men now dead violently—attempts to convene a serious discussion with Stahlman. However, the Professor, blinded by his singular focus on the project, dismisses the fatalities as isolated "personnel problems" and vehemently rejects the Doctor's authority and any implication of a larger crisis. The project's main computer then issues a dire, unequivocal warning, advising an immediate halt to all drilling operations. Both Stahlman and Sir Keith Gold, however, arrogantly dismiss the computer's data as "over-sensitive" and "unreliable," choosing to trust their own flawed judgment over objective data. The situation reaches a critical point when the jar containing the volatile green liquid begins to crack under immense internal pressure. Despite the Doctor's urgent warnings, Stahlman defiantly handles the jar directly, resulting in the visible green discoloration of his left hand—a chilling, undeniable physical manifestation of his own infection and impending retrogressive transformation. He continues to ignore all warnings, asserting his superior judgment above all evidence and expert opinion.

Act 3

Following his increasingly irrational and dismissive behavior, Professor Stahlman escalates his defiance by cutting off the Doctor's nuclear power supply, an act of petty retaliation. He then orders a final, irreversible acceleration of the drilling rate, completely disregarding Petra's desperate, last-ditch plea for caution. Stahlman's left hand is now clearly and visibly green, a stark indicator of his progressing transformation and compromised judgment. The Doctor, anticipating Stahlman's dangerous recklessness and realizing the Professor will not be reasoned with, covertly restores his own power supply, preparing for a direct intervention. Stahlman, however, proceeds to commit a deliberate act of sabotage, removing a crucial micro-circuit from the main computer's control panel, effectively silencing its warnings and rendering it useless. The Doctor, witnessing this egregious act, confronts Stahlman in the Brigadier's office, using a swift application of Venusian karate to disarm him and retrieve the circuit. Stahlman, maintaining his deception, denies possessing the circuit, only to later crush it underfoot in a secluded corridor, destroying the evidence of his deliberate sabotage. Recognizing the immense gravity of Stahlman's actions and the imminent global catastrophe, the Doctor initiates a desperate, covert counter-plan. He enlists Liz Shaw to feed "epsilon coordinates" into the computer's spare bank, a complex calculation designed to avert the disaster. Liz, upon discovering the Doctor's power restored and the main computer broken, pieces together the puzzle of Stahlman's deception and the Doctor's secret, high-stakes maneuvers. The episode culminates with Stahlman detecting the Doctor's unauthorized power usage and cutting it once more, as the TARDIS console shakes violently, signaling the rapidly escalating crisis and the Doctor's increasingly desperate race against time to prevent a world-ending volcanic eruption.