See more of my reviews sooner on Birth of a New Witch! My copy was an ARC I received from the publisher or review.3.5 stars.The Alchemy of Forever, the first book in this series, had its issues, but it was fun book easily consumed in a day, it knew where it was going, and it left off on a killer cliffhanger that encouraged me to read The Impossibility of Tomorrow. The cliffhanger's resolution happens early on and was rather anticlimactic, but overall, The Impossibility of Tomorrow was just as much fun as the first book. Its pacing may have been off and Seraphina got confidential information with too much ease, but I honestly can't say I regret reading the book.Believing Cyrus has found her and it's the end, Sera gets on the ball and stays on it (with an exception or two). When it comes time for her to decide whether or not to kill someone she believes is Cyrus, she's ready to kill one last time to save herself. She comes close to killing innocent people a number of times, actually, but they're always saved by an innocuous detail. This "it's him, it's not him, it's him, it's not him" revolving door can get old, but it keeps readers on their toes because all the red herrings make it hard to figure out who is really him.The exceptions come in small actions, like Sera being seemingly unaware that she can use an attacker's force to impale him on her knife. Another of her more annoying tendencies is to push Noah away thinking it will protect him from Cyrus. Her former lover would be on the lookout for someone acting out-of-character by their friends' standards and with how in love Sera and Noah were in book one, breaking up with him "for his own good" may have put him in more danger than staying with him would! All that romantic drama really slows it down.Despite that uneven pacing thanks to the romantic drama and a few unimportant events, the novel's plot is well-conceived with all its plot points placed just right and the mystery keeps us going. I read most of the novel in a single day because putting it down was difficult even despite the rough patches. Cyrus's true identity? Caught me completely by surprise, though I suppose that character had been acting unlike themselves.However, holes like Reed's unexplained presence/actions (was it explained and I skimmed over it on accident?) and Sera getting confidential patient info hospital laws say she can't get unless she's a family member weaken the plot somewhat. It's still fun, but it's not entirely believable. (The irony is strong with that one, yes, but the existence of immortals does not erase hospital laws.)From what I heard, The Impossibility of Tomorrow is the end of the series, but the ending leaves things open in case Williams wants to come back for a third book or follow other characters in the same universe. Williams has some serious talent, so I'd be willing to read those books if they were written. When you feel like going on a binge with a completed series about immortals, this is a pretty good bet.