The Cabinet of Curiosities — Paul Dowswell

When Lukas Declercq is orphaned, his uncle summons him to Prague, a refuge for Europe's greatest alchemists and natural philosophers. Uncle Anselmus is court physician to Rudolph II, the reclusive and unstable emperor. He is also curator of Rudolph's bizarre Cabinet of Curiosities, a series of vast rooms stuffed with wonders and scientific marvels. As Rudolph retreats further into his fantasy world, the threat of rebellion hangs in the air. Dorantes, a diplomat from Spain, comes with his daughter, Celestina, on a mission from Philip II to persuade Rudolph to give up his heretical ways. Soon Lukas discovers the terrible truth behind Dorantes's mission. But sinister forces have plans for Lukas too, and before he can thwart the plot against the emperor, Lukas must gamble on Celestina's loyalty in order to save his own life.