Marla helps Mike decipher the drawing. Turns out all the scribbles map to a location in the town. Candle Cove is Iron Hill! The two then realize exactly where Bravery Cave is - an old warehouse where Eddie and Mike used to play, against Marla's advisement.
Mike later confesses to Marla that it was he who stabbed his brother Eddie with the hook all those years ago. And then he buried him in the woods. But it was not him who brought Eddie's corpse to the warehouse.