The Battle of the Labyrinth (Percy Jackson and the Olympians, #4)

by Rick Riordan

Now, I want to hear Grover’s story. Again, from the top.” “But, my lord,” Silenus protested. “It’s just nonsense!” Dionysus’s eyes flared with purple fire. “I have just learned that my son Castor is dead, Silenus. I am not in a good mood. You would do well to humor me.”