Belladonna's Promise

Hogwarts Mystery Year 5. From the point of view of Barnaby Lee.
Barnaby's grandmother is fed up with her brainless grandson embarrassing the Lee name at school, she she has issued him a threat: pass every one of his OWL exams, or be pulled out of Hogwarts. Getting all the OWLs is a difficult task for the brightest of students, so Barnaby knows he doesn't stand a chance.
If that weren't enough, another Cursed Vault has been opening, unleashing a new curse upon Hogwarts. Every student is terrified they will be the next to be abducted. Barnaby must help his best friend Sarah lift the curse and pass his exams, before he gets himself killed..."Or worse, Expelled."