What is the exposition in warriors midnight?

The point of the book "Midnight" in the Warriors series is that the clans will know that they have to leave the forest. Midnight is a badger who believes in "Starclan". They choose 1 cat from each clan to travel to the sundrown place. You might be thinking that "Starclan" could of sent the medicine cats a sign, but since i don't know the exact answer, i would guess they didn't send them a sign because they wanted to bring the clans together so each cat could warn their clans without trespassing, or something like that. but its to just warn them that the "Twolegs" are going to destroy the forest and that the the clans will have to leave to find a new home. :D