The Royal Opera House shimmered with an almost unbearable brilliance. Crystal chandeliers blazed, reflecting off the satin gowns and jeweled tiaras of London’s elite. The air hummed with anticipation for Verdi’s “La Traviata,” a tragic tale of love and sacrifice that seemed, ironically, to mock the shallow dramas playing out in the boxes above the stage. Ethan, impeccably dressed in evening tails, felt a knot of grim determination tighten in his stomach. Tonight, the performance playing out offstage would be far more captivating, and far more real.