Final answer:
In the book 'The Lightning Thief', Percy, Clarisse, and Grover use a plan to blind the Cyclops. They attack the Cyclops by using Percy's reflective shield.
Step-by-step explanation:
According to the given information, Percy, Clarisse, and Grover use a plan to attack the Cyclops in the book 'The Lightning Thief'.
In the book, they devise a plan to blind the Cyclops using Percy's reflective shield.
They successfully execute the plan, depriving the Cyclops of his sight and gaining an advantage in the battle.