Complex sentence: Eighteen months later, Banning works at the Treasury Department, within eyesight of the White House; he has been demoted from the Presidential Detail as the sight of him triggers Asher's memories of the night Margaret died.
Split into simpler sentences: Eighteen months later, Banning works at the Treasury Department, within eyesight of the White House. He has been demoted from the Presidential Detail as the sight of him triggers Asher's memories of the night Margaret died.