this one was definitely better than the first I think but the plot was still really cliche and nonsensical.

Klara has ended up back in time after defeating Llaw but Callum isn't anywhere to be found and last she saw, he was dying. Thankfully she ends up with Thomas, Callum's best friend who they also thought dead but is not and who is also magic like her. Thomas and Klara don't know what to do at first but they at least get her into historically appropriate clothing before heading to her house-mind you she doesn't live here and no one knows her because she is their great great great great grandchild. This is where it all starts to fall apart for me: why did they go there? what is their plan? why does she immediately trust him so much? Next we find out

Callum isn't actually dead and is somehow now in Edinburgh in a fairie house underground where they're healing him for no reason and we find out he is half-fae???? Then we're introduced to the main villain Malabron who is only in the book for maybe five seconds and isn't really a big deal at all. (he doesn't even make an appearance in the conclusion). It is immediately revealed to us that although Thomas is hot apparently and Klara and him have chemistry supposedly he is working with Malabron and is evil. Then Klara and Thomas are accosted by ?thieves? but then more bad guys show up and beat up the thieves and then kidnap Klara??? what is going on! Klara spends the next three days kidnapped in a tower but I guess since female damsels in distress are an overdone trope Klara is never seen as weak and always fights her own way out or does it with a team and so it never really seems like she is ever in danger. 
Meanwhile Callum has made another bad deal with the hag to go into the past because apparently he's in the future. When he ends up in the past he is randomly claimed by a local minor nobility who says he's Callum's father who abandoned him cause he's part fae.  He now takes in Callum and pays off Klara's captors to free her. Klara, Callum, and Thomas now reunited are attacked and immediately figure out Thomas is evil. They have a few more minor battles before playing dress up and attending a fancy social outing with Callum's new annoying dad where they discover that the people currently in Klara's house are somehow in the know about her and everything's easy and fine. 
The plot gets wrapped up by Klara and Callum ?traveling through time and space? to kill the hag which somehow solves Callum's curse but also stops Thomas and Malabron's evil plot before it's even started and finishes the book.

Overall I don't feel like the love triangle angle really came into play at all. The characters are continually handed everything and random new characters are introduced just to hand them the next plot point. Also, the reader almost immediately finds out

Thomas

is bad so there's no big reveal and the bad guys in general aren't all that threatening. Overall Klara and Callum are both very powerful and never have any struggles or bad things truly happen to them so in both this book and the first the solutions are so easy and simple for them and there's no real stakes

(ie Callum comes back to life after all and Klara and Callum find a loophole to go to the future anyway).

Another big problem with both books is that it breaks a big time travel rule: when u travel through time you can't also travel locations. I know Doctor Who does and what not but I believe a standard rule when writing time travel is that you can only do one or the other unless you explicitly explain otherwise. Klara and Callum are  traveling through time but also ending up across the country which I found confusing and unbelievable.

The story was a really quick read though, and it is definitely full of tropes and silly little fantasy rom com stuff. I thought all the references to modern day fandom stuff was a bit cringey and cliche though. (And also spoiled the plot of Vampire Diaries).