I feel like there is a lot of continuity throughout AMC songs; in the same vein that "At My Mercy" and "Asleep" were in, this seems to be about somebody that he loves, but who has changed for the worst. He's reminiscing about a moment of bliss that they both had where they literally watched the fireflies and sat on the lawn. At the same time, he's comparing her love to a firefly, since it sparks for a second and then disappears. It's upsetting and brilliant.
I feel like there is a lot of continuity throughout AMC songs; in the same vein that "At My Mercy" and "Asleep" were in, this seems to be about somebody that he loves, but who has changed for the worst. He's reminiscing about a moment of bliss that they both had where they literally watched the fireflies and sat on the lawn. At the same time, he's comparing her love to a firefly, since it sparks for a second and then disappears. It's upsetting and brilliant.