Simplify the following text for a Grade 7 native English-speaking person.
Original: Percy and Annabeth decide to go as well , not just for the Golden Fleece , but for their friend Grover who is trapped in Polyphemus ' cave .
Simplified: Percy and Annabeth decide to go also , not just for the Golden Fleece , but for their friend Grover who is trapped in Polyphemus ' cave .