Clockwork Prince by Cassandra Clare 
The situation at the London Institute has never been more precarious. With Mortmain and his clockwork army still threatening, the Council wants to strip Charlotte of her power and hand the running of the Enclave over to the unscrupulous and power-hungry Benedict Lightwood.
In the hope of saving Charlotte and the Institute, Will, Jem, and Tessa set out to unravel the secrets of Mortmain’s past—and discover unsettling Shadowhunter connections that hold the key not only to the enemy’s motivations, but also to the secret of Tessa’s identity. Tessa, already caught between the affections of Will and Jem, finds herself with another choice to make when she learns how the Shadowhunters helped make her a “monster.” Will she turn from them to her brother, Nate, who has been begging her to join him at Mortmain’s side? Where will her loyalties—and love—lie? Tessa alone can choose to save the Shadowhunters of London…or end them forever.
The second book in the Infernal Devices series (and part of the prequel to the Mortal Instruments series) was an excellent mixture of action, adventure, Victorian England propriety, and fantasy. Everything rolled into one in this book and I thoroughly enjoyed it. In comparison to Clare’s first book of the Infernal Devices series (Clockwork Angel), which contained several explanations for the Shadowhunter world and Victorian mannerisms, Clockwork Prince picked up where readers left off with the cast of characters and continued the mesmerizing story.
Also worthy of noting is the lack of slow pacing. I’ve noticed that the middle books of series tend to read more like fillers and plot development, something to keep readers entertained before the final showdown. While Clockwork Prince does contain elements of this (linking Mortmain from the first book, discovering his past in this book, and possibly his ruin in the next — spoiler?), I felt like I could pick up this book without having read any of Clare’s work and understood it perfectly. That’s what is so great about Tessa’s character: she herself is new to the Shadowhunter world. The reader discovers everything with her, and the explanations are clear and to the point in this second installment. That leaves enough room for the plot to develop, Victorian aspects of life to take over, and of course (what is young adult literature without this?) a touch of romance to flourish.
EDIT: Also, if you love 19th-century British literature, especially Jane Eyre, Wuthering Heights, Tenant of Wildfell Hall, Tale of Two Cities, Byron, Tennyson, or Rossetti, you’re in for a treat. Several references, quotations, and parallels throughout.
Rating: ★★★★.5 of 5
GoodReads: 4.28 of 5