Grover is undercover once again, this time at a military school, where he discovers two children, Nico and Bianca di Angelo, that he suspects are half-bloods. In the excitement of his discovery, Grover asks Percy to come and help him safely bring the half-bloods to camp half-blood. In the process of trying to get to the di Angelos, a manticore (Dr. Thorn) attempts kidnaps Percy, Bianca, and Nico, only to lose them to Thalia, Annabeth, and Grover. As they battle Dr. Thorn, the Hunters of Artemis step in and rid of the monster by making him trip off a cliff, which led to the loss of Annabeth, her being on Thorn's back. Artemis leaves her Hunters to be escorted to Camp Half-Blood by Percy, Grover, and Thalia. Artemis is then kidnapped, which means that a quest must be launched to save her. That quest consists of Grover, Bianca (who is a new Hunter of Artemis), Zoe Nightshade (The chief Hunter of Artemis), Thalia, and Percy, who journey across the country to Mt. Tampalais. On the way, Grover is involved in several situations where Pan, god of the Wild, speaks to him. The first was in Cloudcroft, New Mexico, where the presence of Pan made the birds on Grover's coffee cup and a rubber rat come to life, also bringing a giant wild boar to help Percy, Thalia, him, Bianca and Zoe escape the skeletal army. The second incident happened when Grover was alone. Pan spoke to him, saying, "I await you." Both times, Grover was drinking coffee, so he and the other satyrs believe, that this had something to do with Pan's appearance.