Original: In the process of trying to get to the di Angelos, Dr. Thorn (who is a manticore) attempts to kidnap Percy, Bianca, and Nico.
Simplified: 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.