Lyric discussion by Amhil 

I thought it maybe was about someone who fought in a war and survived, but has seen terrible things. The fair-faced young man can both be reference to a friend he lost, or to himself (who is now not that bright faced and eager anymore, after everything...)

He goes back home and carries on living a normal life, he tries to forget ("You carried their dead weight and let it fall by the wayside and buried those years one dark evening") but he still remembers everything that happened ("Keep the secret")

The song is a kind of mantra for this person to keep going ("Plumb and level", to be normal and well adjusted) and to leave the war behind him ("Stow the shovel") and try to be happy even though terrible things happened ("Keep the Joy"). This person might seem somewhat withdrawn from society and antisocial ("Keep the quiet") but this is not what is going on inside his head... ("No, you're not shy, keep the fire... smoldering")

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