The Unfortunate Tales of Alex and Harmony

This is a collection of stories about Harmony, My main Harry potter OC (hence my name), and my friends OC, Alex. So Alex is Quidditch captain and is the master at herbology and Harmony is the near opposite. She is Apprenticing Charms and is a star student.
What happens when Harmony leaves her prefect badge at school when she's away for a couple of weeks?
What will happen when Alex looking into Harmony's diary?
What Chaos will ensue around these two opposite but close friends?
Read to find out!