More like 3.5 stars but I'm rounding down at the moment because it just stopped rather than ended. There was absolutely no climax to the book. I actually thought the epilogue was a very short chapter and was stunned when there was no more. I suppose that's because it's the middle book of a trilogy story, but it was still an unpleasant surprise. 
 In general the characterizations were stellar, but in the second half, both Sorcha and Seth developed strong emotions that felt too powerful for the scenes together we'd seen. Sorcha in particular I would have appreciated seeing more of pre-Seth. 
 What I loved about the book was how everybody has their flaws in the series. I really enjoy seeing how those flaws and their loves manage to create strife between good people who would prefer to be friends. And I like almost all of the characters a great deal. 
 This book does not follow directly on the previous novels, by the way. There's at least one short story that takes place between Ink Exchange and Fragile Eternity that changes the landscape considerably. I read it without reading the story and once I understood that I HAD missed something and not massively failed INK reading comprehension, it wasn't too bad. But still, fair warning.