During the Time War in Arcadia, while an instructor adjusts a headcam (a recording device linked directly to the brain) of a young man newly recruited, he tells him about the device’s side effects including hallucinations so he shouldn’t consider the images that could come into his brain as premonitions. The instructor also tells him that, in case of death, all the memories recorded by the device will be extracted and placed in a “family drive”.
The new soldier then meets his commander, who gives him an introductory speech about their defenses. He describes the “sky-trenches”, planetary defenses that hold back invading forces, telling him that there are four hundred of them guarding Arcadia and that nothing in history has ever breached two of them. The instructor takes the soldier to a defensive turret and instructs him on using scanners to check for objects in the sky. He tells the soldier that they must be thorough and vigilant, as it would only take one Dalek to wipe out the entire city. The instructor directs the soldier to zoom in on a potential target – which he assumes is a bird – but is horrified to see that it is in fact a Dalek. One Dalek quickly turns into many more, and the skies fill with the invading forces. A Dalek fires its extermination ray at the soldier, who screams as the headcam display flashes red and then fades to static.