Revenge is a nasty lady, don't you think?

This story is lightly based off of a song called Don't Lose Your Head and the song is from a musical (I think it's broadway, I haven't actually seen it before) It starts out with Kaachako but Bakugou is unloyal so Ochako decides to do something about it. Some other ships will come up in the story, I don't think I'm gonna tell you guys what the main ship is just yet but I'll tell you that it's a polyamourus. A side ship that I know I will definetly put in is Kirideku, maybe a bit of Kamijirou too. Sorry this is so long, you may continue to the story now.