Well this was a little disappointing.
I definitely think the first book could have been a standalone if

they hadn't killed her mom.

It had all of the character development and growth and I don't think this book really wrapped anything up that hadn't already been finished in the first one. This book just felt unnecessary.
I liked the idea of the retelling of a Greek hero story that was clearly the plot of this book, but it didn't really work for me. I felt like Bri was much more passive in this book than she had been in the first one. She was kind of just going along with everyone else and didn't really do anything to move the story forward or even help with the adventure aspect. Even when she got caught by the others, she didn't do anything but wait to be rescued.  It felt odd for her character to just let the people around her make the decisions. She didn't even do anything special to bring the heart together like everything was implying it would need. I don't know why Circe felt like Bri needed to be there at all or why Hecate singled Bri out for this when

Circe did most of the work and Persephone was the one to give up her life.

I did enjoy the moments we got with Bri and Marie. They were cute together and I wish there had been more to develop their relationship farther.
Overall, I felt like this book did nothing to further Bri's growth or even tie up any loose ends because everything is was mostly done with the first one. I think this duology could easily be just a standalone with the first book.