Get off Epona and talk to the man here to receivethe Lantern. Head back to the tunnel you came from (without enteringit) and take the path at the right of the tunnel this time. Slash theenemy at the entrance of the cave and head inside. Light the torchesinside to light up your way and burn the spider webs blocking yourpath. When you get to the fork, head right and defeat all the enemiesto make a chest appear. Open it to find a Yellow Rupee. Then exit thecave and you'll end back up outside Faron Woods in the swamp area.
Head forward up to a gate in the mountainside (onthe left). It's locked, so run northwest to find another opening behindthe cliff. Enter the cave and open the chest inside to find a SmallKey. Then light up the two torches on each side of the chest (with thelantern) to make another chest appear. Open it for a Heart Piece. Withthe key in hand, return to the locked gate southwest of there and openit with the key. Head inside and follow the path to the very end tofind the monkey and the kid locked in a cage. Break it open with a fewsword slashes to free the kid and you'll return home safe and soundwith him.