Luna (Moon) is a love song built on one sweet, slightly ridiculous idea: the moon, which looks the same "en los Andes o en Japón" (in the Andes or in Japan) and lights up every sky, one day just stops "en mi balcón" (on my balcony). Camilo can't believe it. Maybe it's where she arranged "pa' verse con el sol" (to meet up with the sun), or maybe she got tired of circling the world. "No puede ser por mí, debe haber un error" (It can't be because of me, there must be a mistake).
But it wasn't a one-night thing, "no fue una noche y adiós" (it wasn't one night and goodbye). She came back and back until "se hizo rutina y se quedó" (it became routine and she stayed). The best image is in the second verse: she has seen emperors and palaces, she rubs shoulders with the stars, "y ahora está desayunando en la cocina" (and now she's having breakfast in the kitchen). Then a clever flip on the moon's phases: he thought his mood changed with her phases, but she was llena (full) because he was happy, not the other way round. The song ends with a child's voice saying that when she grows up and becomes a mom she wants to be a firefighter, and a builder too.
Learner tip: "codearse con" means to rub elbows with, from codo (elbow).