Two short stanzas set a gentle image against a threatening one. The first gives us a violin's flutter drifting over open fields, a soft, light sound that fits the calm of the title. Then the second stanza turns the scene. The speaker wonders about "secret armies" arriving quietly in a place "where it storms," and the peaceful picture suddenly feels uneasy.
The poem doesn't explain who these armies are, and that's part of its pull. One reading is that the violin's trembling notes sound like distant troops creeping closer, or like the first stir of a storm gathering. Another is that the music itself is the army, slipping in softly while weather rages around it. Either way, the speaker seems both curious and wary, asking a question rather than stating an answer.
The mood is hushed and tense. Beauty and menace sit side by side, and the quiet in the poem feels like the calm just before something breaks.