Fabula
S4E25 · The Moonbase Part 3

Polly deduces Cybermen’s solvent weakness

In the moonbase sickbay, Polly—frustrated by the companions’ lack of a viable strategy against the Cybermen—seizes on Jamie’s offhand remark about 'sprinkling witches with holy water' to trigger a scientific breakthrough. While Ben dismisses the idea as impractical, Polly’s analytical mind connects the dots: the Cybermen’s chest units (a plastic-like material replacing their organs) might be vulnerable to solvents. She proposes testing acetone (nail varnish remover) as a weapon, shifting the group’s dynamic from passive observation to proactive problem-solving. The moment marks a critical pivot—Polly’s intellectual curiosity and Jamie’s unintentional insight become the catalyst for a potential counterattack, offering hope against the Cybermen’s otherwise unstoppable threat. The exchange also underscores the companions’ complementary strengths: Jamie’s folk wisdom, Polly’s scientific reasoning, and Ben’s pragmatic skepticism, which together form the foundation for their eventual resistance.

Plot Beats

The narrative micro-steps within this event

1

Inspired by Jamie's remark about holy water, Polly realizes that the plastic component on the Cybermen's chest units might be vulnerable to solvents, prompting her to plan an experiment.

Despair to inspiration

Who Was There

Characters present in this moment

4

Skeptical → Engaged → Cautiously supportive

Ben engages in the conversation with a mix of skepticism and pragmatism. He initially dismisses Polly’s idea as impractical but provides critical details about the Cybermen’s suit materials (metal and plastic) and the dangers of the Gravitron power pack. His tone is cautious, but he ultimately supports Polly’s experimental approach, demonstrating his willingness to adapt and collaborate. His naval background informs his practical assessment of the situation, balancing Polly’s optimism with grounded realism.

Goals in this moment
  • To ensure any proposed solution is feasible and grounded in reality, given the high stakes of the Cybermen invasion.
  • To provide accurate information about the Cybermen’s weaknesses and the moonbase’s resources to inform their strategy.
Active beliefs
  • That the Cybermen’s plastic chest units are a potential vulnerability, but only if a safe and effective solvent can be identified.
  • That the Gravitron power pack, though powerful, is too dangerous to use as a weapon against the Cybermen.
Character traits
Skeptical (initially) Pragmatic Supportive (eventually) Knowledgeable (about Cybermen and moonbase systems)
Follow Ben Jackson's journey

Frustrated → Determined → Hopeful

Polly is seated in the sickbay, examining her battered fingernails, when Jamie’s remark about 'sprinkling witches with holy water' suddenly captures her attention. She pivots from frustration to intense focus, her scientific mind latching onto the metaphorical connection between holy water and solvents. She interrogates Ben about the Cybermen’s suit materials, deduces their plastic chest units are vulnerable, and proposes testing acetone (nail varnish remover) as a weapon. Her tone shifts from exasperated to determined, and she prepares to conduct an experiment, embodying the role of a quick-thinking problem-solver.

Goals in this moment
  • To identify a weakness in the Cybermen’s armor that can be exploited to stop their invasion.
  • To validate her hypothesis about acetone dissolving the Cybermen’s plastic chest units through experimentation.
Active beliefs
  • That the Cybermen’s plastic components are vulnerable to chemical solvents, given their similarity to nail varnish.
  • That Jamie’s folk wisdom, though seemingly unrelated, can inspire scientific solutions in desperate situations.
Character traits
Analytical Resourceful Determined Quick-witted Proactive
Follow Polly Wright's journey

Relieved → Playful → Slightly pained

Jamie, recovering from a head injury, attempts to get out of bed but is gently pushed back by Polly and Ben. He makes a lighthearted remark about 'sprinkling witches with holy water,' which he recalls from his 18th-century past. Though he winces slightly from lingering pain, his playful tone and willingness to engage in the conversation highlight his improving health. His offhand comment inadvertently becomes the catalyst for Polly’s scientific breakthrough, demonstrating how his folk knowledge can unexpectedly contribute to their survival.

Goals in this moment
  • To reassure Polly and Ben that he is recovering and capable of contributing to their plans.
  • To share his historical knowledge, even if it seems unrelated, as it might spark new ideas.
Active beliefs
  • That his experiences from the past, no matter how seemingly trivial, might hold value in the present.
  • That teamwork and shared ideas are essential for overcoming the Cybermen threat.
Character traits
Playful Resourceful (unintentionally) Recovering but resilient Thoughtful (despite pain)
Follow Jamie McCrimmon's journey
Supporting 1

N/A (Collective, hive-minded entity)

The Cybermen are indirectly referenced as the primary antagonists whose weaknesses Polly, Ben, and Jamie are discussing. Their chest units, made of a plastic-like material, are identified as a potential vulnerability to solvents like acetone. The companions’ conversation reveals the Cybermen’s cold, logical nature and their reliance on technology to suppress organic life. Their presence looms over the scene, driving the urgency of the companions’ efforts to find a countermeasure.

Goals in this moment
  • To convert all organic life on the moonbase into Cybermen to expand their collective.
  • To activate the Gravitron to control Earth’s weather and eradicate all organic life on the planet.
Active beliefs
  • That organic life is inferior and must be eliminated or converted to ensure the survival of the Cybermen collective.
  • That their technological superiority makes them invincible to organic resistance.
Character traits
Logical (coldly efficient) Technologically dependent Dehumanizing (viewing organics as threats)
Follow Cybermen (Collective)'s journey

Objects Involved

Significant items in this scene

4
Cybermen's Chest Unit Plastic

The Cybermen’s chest units, made of a plastic-like material, are identified by Polly as a critical vulnerability. She deduces that acetone (nail varnish remover) can dissolve this plastic, offering a way to disable or destroy the Cybermen. This object is central to the companions’ strategy, as its weakness provides the foundation for their counterattack. The discussion about its composition shifts the group’s focus from radiation (Gravitron) to chemical solvents, marking a turning point in their planning.

Before: Intact and functional on the Cybermen, housing their …
After: Identified as a target for acetone-based dissolution, pending …
Before: Intact and functional on the Cybermen, housing their vital organs and cybernetic components.
After: Identified as a target for acetone-based dissolution, pending experimental validation.
Gravitron Power Pack

Ben mentions the Gravitron power pack as a potential source of radiation to target the Cybermen, but immediately dismisses it due to its extreme heat (four million degrees). While this object is not directly used in the event, it serves as a contrast to the acetone solution, highlighting the impracticality of high-tech weapons in favor of simpler, more accessible methods. Its discussion underscores the companions’ need for a feasible and safe countermeasure, reinforcing the importance of Polly’s acetone proposal.

Before: Operational on the moonbase, generating thermonuclear energy for …
After: Dismissed as a viable weapon due to its …
Before: Operational on the moonbase, generating thermonuclear energy for the Cybermen’s plans.
After: Dismissed as a viable weapon due to its extreme danger and inaccessibility.
Holy Water

Jamie’s remark about 'sprinkling witches with holy water' serves as the metaphorical and conceptual catalyst for Polly’s scientific breakthrough. Though no physical vial or container of holy water is present, the phrase sparks the idea of using solvents to dissolve the Cybermen’s plastic chest units. This object (or rather, the concept of holy water) bridges Jamie’s 18th-century folk wisdom and Polly’s modern scientific reasoning, demonstrating how seemingly unrelated knowledge can inspire innovative solutions in desperate situations.

Before: A metaphorical reference from Jamie’s past, invoked in …
After: Translated into a tangible plan to use acetone …
Before: A metaphorical reference from Jamie’s past, invoked in conversation.
After: Translated into a tangible plan to use acetone (nail varnish remover) as a weapon against the Cybermen.
Nail Varnish Remover

Polly identifies acetone (nail varnish remover) as a potential solvent to dissolve the Cybermen’s plastic chest units. She proposes testing it as a weapon, shifting the group’s focus from passive observation to proactive problem-solving. The object is not physically present in the scene but is referenced as a readily available resource on the moonbase. Its role is pivotal, as it offers a feasible and low-risk method to exploit the Cybermen’s vulnerability, providing hope in the face of their otherwise unstoppable threat.

Before: Stored somewhere on the moonbase as a common …
After: Identified as a critical component of the companions’ …
Before: Stored somewhere on the moonbase as a common household or maintenance item.
After: Identified as a critical component of the companions’ counterattack plan, pending experimentation.

Organizations Involved

Institutional presence and influence

1
Cybermen

The Cybermen, as a hive-minded collective, are the primary antagonists driving the companions’ urgency to find a countermeasure. Their invasion of the moonbase and plan to weaponize the Gravitron to control Earth’s weather create a existential threat, forcing the companions to think creatively. The organization’s cold logic and technological superiority are contrasted with the companions’ organic adaptability and resourcefulness. The discussion about the Cybermen’s plastic chest units and the acetone solution reflects the companions’ determination to exploit even the smallest weakness in the Cybermen’s armor.

Representation Via the companions’ discussion of their weaknesses (plastic chest units) and tactics (conversion, Gravitron activation).
Power Dynamics Exercising overwhelming authority over the moonbase, with the companions operating under constraint and desperation.
Impact The Cybermen’s presence underscores the stakes of the companions’ efforts, as their invasion represents a …
Internal Dynamics None explicitly shown, as the Cybermen operate as a unified, hive-minded collective with no internal …
To convert all organic life on the moonbase into Cybermen to expand their collective. To activate the Gravitron to control Earth’s weather and eradicate all organic life on the planet. Technological superiority (Cybermen suits, Gravitron power). Psychological pressure (threat of conversion, existential dread).

Narrative Connections

How this event relates to others in the story

What led here 3

"The Cybermen revealing their plan to destroy Earth directly motivates Polly and Ben to search for a way to stop them, leading to Polly's realization about the plastic's vulnerability."

Cybermen seize control room and declare Earth's extinction
S4E25 · The Moonbase Part 3

"The Cybermen revealing their plan to destroy Earth directly motivates Polly and Ben to search for a way to stop them, leading to Polly's realization about the plastic's vulnerability."

Cybermen reveal Earth's extinction plan
S4E25 · The Moonbase Part 3

"The Cybermen revealing their plan to destroy Earth directly motivates Polly and Ben to search for a way to stop them, leading to Polly's realization about the plastic's vulnerability."

Cybermen reveal infiltration and extinction plan
S4E25 · The Moonbase Part 3
What this causes 1

"Polly and Ben's discussion about how to defeat the Cybermen leads to Polly testing acetone and discovering it dissolves plastic, giving them a weapon."

Polly and Ben develop the solvent weapon
S4E25 · The Moonbase Part 3

Key Dialogue

"JAMIE: Well, in my day, they used to sprinkle witches with holy water."
"POLLY: Sprinkle. Holy Water. Ben? BEN: Yeah? POLLY: What are the Cybermen covered in? BEN: As far as I know, their suit is a metal of some sort. POLLY: Oh. What about that thing on their chests? You know, the part which replaces their heart and lungs. BEN: Some kind of plastic, I think. POLLY: I thought so. You see, it's simple. Nail varnish remover dissolves nail varnish. Nail varnish is a plastic. So we do what Jamie says. We sprinkle them, see?"
"BEN: No, I don't. Clear as mud if you ask me."