:OO
I listened to The Rumor while reading the lyrics cause I thought it was extremely ironic after Tsuki's fancam (That's her nanananana For real? nanananana)
But I didn't get any of that "exposition, dialogue, monologue"
Actually I thought it was kinda boring/basic as a song
well, it will be too long to be explained since I must explain their whole lore..
but the tldr is :
that song is like the title, The Rumor. Their friend named Billlie is missing and they kinda run away / denial about it. Some verses are their neighbor who are gossiping about the disappearance.