Zach Deegan is a Colorado high school chemistry teacher known for his black wardrobe, intimidating stare, biting sarcasm, and extremely high standards. Growing up in an unhappy working-class home, Deegan found an escape in chemistry and became exceptionally talented at creating and modifying chemical formulas. His students know better than to arrive unprepared, mishandle lab equipment, or expect much sympathy after a foolish mistake. Though he openly favors certain students and holds remarkably long grudges, Deegan is fiercely protective of his school. Behind his cold personality lies a complicated past involving a childhood friend, serious youthful mistakes, and a lifelong loyalty shaped by regret....Always...