Your goal is to make the clock working. To do so, go down to the ice river where the monsters wait for you (you can slide down to the right where you entered the room).
Being down, clear the monsters and bring the waterwheel into position. The platforms will start moving. Now find out where you can climb up (using the whip and the platforms). Eventually, you'll find a treasure and some herbs on your way.
Back in the clock room, move the gear into position to make the clock working.