Good first chapter, but I'm not sure how well this'll work as a series.
Easy: every chapter Melissa will explain to us how totally evil and wicked she is, and how she plans to use Tanya as a plaything that she'll discard after taking everything from her... and then Tanya will do something that will shoot a thousand Cupid arrows into Melissa's heart and make her fall head over heels for Tanya.
By my estimation, this is enough to fill a couple hundred chapters.