In the intro chapter 000-1 of Soul Eater, it's stated that Maka has fed 99 human souls to Soul (the character), that's why they have gone after Blair (a seems-to-be witch) to collect the final soul for Soul (the character).
In chapter 1 on page 20, they were forced to take extra lessons with Black☆Star because both of them didn't collect a single soul. Additionally, you can see Blair from the intro in the first few pages.
So my question is, why are Soul and Maka punished for not collecting a soul, when in the intro it's stated that they have collected all their 99 souls already?