Instructions
Look under Sam's bed to find the lunchbox before embarking on his adventure. Click on the trash can on the left side of the screen to find it if the lunchbox is not under the bed.
Check next to the wishing well to find your lunchbox is during Sam's adventure. If the lunchbox is there, Sam won't be able to reach it. Return to the boat Otto to get to the lunchbox another way.
Travel downriver, going up and left. Go past the abandoned shack and down the waterfall to fall into the caverns beneath it.
Look in this part of the caverns to find your lunchbox if it was not by the wishing well. Use the magnet and click on the lunchbox to attract the metal container if it is in the water.
Go left once you are in the caverns if the lunchbox was by the well. Use the oars to go against the current up the path to the well. Click on the bucket to travel up the well and get the lunchbox.