Draco Malfoy wasn't nearly the Library Mouse that Granger was, but he knew his way around easily enough. The Herbology books were on the second floor - little used as they were, he ascended the ladder easily, wishing he was on his broom. But he had no time for such stray thoughts. The essentials of a plan were sizzling in his mind, like little rays of lighting fizzling and lighting anew.
He sent a practiced eye over the firstie books - he had them memorized, of course. The second year books were quite familiar to him, even the ones most considered only useful for extra credit. Extra advantage was the way the Slytherin mind bent, and he had read them cover to cover, even if Prof. Sprout knew nothing of it.
The third year books were passing strange, but mostly because he had been... preoccupied. If he didn't have this solved by summer, he'd lay whatever was bothering him aside and finish the year by being schooled in everything. His godfather and mother would help with that - Potions and Charms were his harder subjects, even if he generally did well at them.
He reached instead for the theoretical books, knowing that he needed to stretch out firm rootstock, in order to make this plan work. He couldn't leave anything to chance or error. Herbology was widely considered a duffer's subject, but Draco was about to make it his own.
[a/n: "break it worse" is a traditional engineering trick. Generally doesn't involve libraries.]