Back before she wrote the Mortal Instruments series, Cassandra Clare became mildly famous (and infamous) for the novel-length Harry Potter fanfics she wrote. 
 So what do you get when you combine the Mortal Instruments with Harry Potter? You get "Welcome To Shadowhunter Academy," a novella that kicks off a series of new short stories following a new group of young Shadowhunters-in-training in a long-abandoned Academy. It's pretty standard school-of-magic stuff, and honestly the development of the newly de-vampirized Simon is what is most interesting about it. 
 Yes, that Simon. He has left home to join the newly-reopened Shadowhunter Academy in Idris. Since most of the Shadowhunters have been killed, they are now recruiting teens from far and wide to be trained -- some are from long-lost Shadowhunter families, and others are mundane orphans who have nothing to abandon. And in Simon's case, he wants to reclaim some of the cool he lost when he stopped being a vampire, so he'll be a worthy boyfriend for Isabelle. 
 The Academy has its own problems -- non-functioning toilets, vats of vile soup, demon possums, and so on. But what really bothers Simon is the sharp divide between those with Shadowhunter blood and the mundanes, aka "dregs," who are taught in different classes. And he's suspended between them, since he is a mundane who has sorta kinda proven himself. Also, he has made a friend in his much hotter roommate, George. 
 It's a little difficult to sum up "Welcome to Shadowhunter Academy," primarily because it doesn't really have a plot on its own -- there are tiny, tiny hints that there is something brewing in Idris that could be potentially be interesting, but nothing concrete. It's basically those chapters in every post-Harry-Potter series about magical schools when the main characters are getting used to their new environment, taking classes and and getting acquainted with the important characters. This includes bigotry against the mundane "dregs," which is pretty much standard by now. 
 Admittedly, it is interesting to read a story where the school in question is in pretty wretched condition, since Sarah Rees Brennan assures us of the decrepit state of the academy -- broken stained-glass windows, ooze-encrusted dungeons, bathrooms in non-working order, and so on. It takes some of the glamour out of learning magical stuff when it happens during a slow renovation. 
 And Sarah Rees Brennan's writing is quite strong here, painting a glittering picture of the City of Glass and the surrounding lush meadows, as well as a sense of danger from the wildness of the forests around the Academy (Simon keeps trying to find out if there are bears). Unfortunately -- as in the Mortal Instruments series -- the attempts at snarky wit fall pretty flat ("Do tell me more about Shadowhunters, and their occasional tendency to be unfair. I will find it fascinating and surprising"). 
 Simon continues to probably be the most likable person in the series, mainly because he's the most ordinary. And that is what most of "Welcome To Shadowhunter Academy" rides on -- the fact that he IS an ordinary person, and he feels that his lack of power, strength or skill is what defines him. So the plot of this story is effectively that Simon needs to learn his worth as a person, and that it's not his vampire "suaveness" that attracted Isabelle. 
 George makes a pretty good counterpoint to Simon, being everything that Simon is not (super-attractive, athletic, Shadowhunter by birth), and it's nice to see the "underwear model" being the sidekick for once. Unfortunately, few of the other characters have much to really distinguish them, and some of them -- like Marisol or Julie -- might as well be paper dolls for all we know of them through their behavior. 
 "Welcome to Shadowhunter Academy" isn't so much a standalone story as an introduction to a serial story -- it's mostly about the main character getting settled in his new home, and stopping when the author felt like it. It's an interesting beginning, but only a beginning.