Golden Sun: The Lost Age/Venus Lighthouse

Venus Lighthouse
Now don't expect to be able to get into any proper gameplay for a good 5 minutes, there's a lot of dialogue to get through. Probably longer if you read it all (recommended).

After all the dialogue you will finally have control. From here go west and through the door, follow your way around this room and go through the southern door. In this room go all the way to the east and through the door, you will find a room with a whole lot of blocks to jump along. Follow the red blocks on the image to guide your way. Go through the door and there will be a treasure chest which contains an Herb. Now go back across the blocks and through the door. Back in here go to the middle of the room and go through the door at the south of the room to get into the next room. Now go through the next door to the south and then the next to reach the exit of Venus Lighthouse.

Outside Venus Lighthouse
Now that you're outside, head towards the small set of stairs.