The story of Captain America: Civil War is one of responsibility, broken friendships, and loyalty. To underline these great tensions, Henry Jackman brings in stabbing strings, machine-gun snare drums, and dread-inducing brass for the moments of high excitement (“The Tunnel,” “Standoff”), and eerie whistles and long, worried notes that intertwine and rise to a fearful climax for the anxious lulls (“Boot Up,” “Ancestral Call”). Then there are the grave melodic descents (“Stepping Up,” “Catastrophe”), where our superheroes have to face the consequences of their actions.