The Lighthouse at the World's End | 
pickThe 4th and last book in the series about Nine and her friends that started with “The House at the Edge of Magic”
I‘m not going to say too much about what happens, but here‘s some words from the blurb at the back:
A stolen locket
A dangerous deal
A toilet on the run
I‘m so glad this series showed up in my search results at the library when I was searching for something completely different.
Cupcake12 This sounds like a fun read! 5d
peanutnine A toilet on the run! 😂 Sounds fun! 5d
tina_b.ooks Also such a beautiful cover 😍 5d