Master's Naval Sabotage Call Device

A jury-rigged communication device fashioned from stolen naval components, used to demonstrate the Master's involvement in UNIT naval system sabotage.

4 appearances

Purpose

To serve as a makeshift communication device that demonstrates the Master’s access to and manipulation of human naval technology, thereby exposing his involvement in the sabotage of the submarine’s systems.

Significance

The device acts as a critical piece of evidence linking the Master to the cyber-espionage affecting UNIT’s naval assets. Its existence forces institutional stakeholders like Captain Hart to confront the reality of an alien adversary capable of infiltrating human infrastructure. Hart’s concession to the Doctor’s demands, catalyzed by this device, marks a pivotal power shift in the episode’s escalating conflict.

Appearances in the Narrative

When this object appears and how it's used

4 moments

S9E12 · The Sea Devils Part 4

Hart concedes to the Doctor's urgent plea

The Doctor describes the Master’s calling device as a jury-rigged communication tool fashioned from stolen naval components, using this narrative device to collapse Hart’s fantasy dismissal and pivot to actionable intelligence—implied presence rather than physically shown.

Before: Unseen but implied through the theft of spares and the Doctor’s subsequent reference to it

After: Established as a credible threat mechanism despite Hart’s initial dismissal of its technical possibility

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S9E12 · The Sea Devils Part 4

Hart concedes under Doctor’s proof

The Master’s calling device is indirectly implicated through the Doctor’s reference to the stolen spares and the confirmation of their theft. While not physically present, its narrative role as the tool enabling the Master’s control over the sea creatures and leverage over Trenchard is central to unifying the scene’s disparate threats under a single, dangerous source.

Before: Jury-rigged and hidden, its existence tied to the stolen components

After: Implied validity and presence through Hart’s reluctant acceptance of the theft

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S9E12 · The Sea Devils Part 4

Mundane sandwiches amidst escalating crisis

Though physically absent in this segment, the calling device is referenced contextually as the reason the Doctor pivots away from Sea Devil warnings. Its existence becomes a bridge from absurdity to credibility, as the Doctor implies Hart's skepticism can only be challenged through tangible sabotage.

Before: The calling device exists as an implication, fashioned from stolen spares.

After: Its existence is acknowledged conceptually by the Doctor as a means to prove the Master's involvement.

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S9E12 · The Sea Devils Part 4

Hart forced to confront Sea Devil threat

The Master’s calling device, fashioned from the stolen spares, is implied rather than shown; the Doctor references its existence using the spares theft as evidence of a direct link to the alien signal or control mechanism. It becomes the symbolic pivot from abstract theory to confirmed sabotage.

Before: Awaiting repurposing by the Master using stolen naval components

After: Functional device enabling the Master to remotely control human pawns and alien allies

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