Original: Annabeth and Percy ask Tantalus to send somebody on a quest to find the Golden Fleece, which he does, sending Clarisse.
Simplified: Annabeth and Percy ask Tantalus to send somebody on to find the Golden Fleece (the wool of a golden-haired sheep in Greek mythology). Tantalus sends Clarisse, the daughter of the god of war, Ares, to get the Fleece.