I wouldn't necessarily call this a PWP book (that's "Plot? What Plot?" for those unfamiliar with fanfic terms), but the plot is really only there so we can spend some more time with the characters. The setup is fun, and there are plenty of shenanigans that reminded me of a Disney movie. Ultimately, though, this is about the characters. There are also a lot of sweet moments between Elisabeth, Nathanial, and Silas, but we also get to explore some of the darker bits, like Nathanial's past, or the impact on relationships when one person is immortal, and one isn't. 

I do hope that the author is planning more books in this universe. There's a brief, almost throwaway line, where Elisabeth considers if it isn't possible to be something in between a warden and a conservator, and I would love to see her get the chance to explore that. Also, this world just has a cozy feel to it, and I enjoy spending time with these characters.