leave the world behind what happened

Short version: a coordinated, man-made cyberattack yanks the plug on modern life—comms die, navigation glitches, and fear fills the gaps. As G.H. explains, it’s a three-stage destabilisation: isolate people, dial up chaos (sonic booms, misinformation, strange “accidents”), then invite a convenient “saviour” to restore order. The deer and other eerie touches aren’t supernatural; they’re mood-setters while infrastructure and trust unravel. By the end, the world hasn’t exploded so much as stalled—power, news, and certainty all offline—while Rose slips into a neighbour’s bunker and finally watches the Friends finale. It’s deliberately ambiguous, but the gist is engineered chaos, not aliens or prophecy.