Complex sentence: Some time later, Andy recounts this story around a campfire in the ruins of London, explaining how the destruction of Newton Haven was accompanied by a worldwide electro-magnetic pulse that wiped out modern technology and set humanity back to the Dark Ages.
Split into simpler sentences: Some time later, Andy recounts this story around a campfire in the ruins of London. The destruction of Newton Haven triggered a worldwide electro-magnetic pulse that wiped out modern technology and set humanity back to the Dark Ages.