"The Midnight Feast" by Elizabeth Pulford.
Mele has been reading this book and Lani is her DJ for this podcast. These girls are both in Room 17. The story is about two girls, Tilly and Rosie, who are best friends, but then Margaret comes to stay. Why did she have to come and spoil it all with her tap dancing shoes and make-up? The Midnight Feast they had planned for Tilly's birthday looks like it is going to be ruined.