text: In Chapter 11 The dwarves find the secret door to the dragon's den because they hear a thrush knocking (that is a type of bird) and it makes them look over at a hole in a rock that is shaped like a keyhole and the setting sun shines through the keyhole and casts light onto the secret door.\n\nThe treasure that Bilbo takes from the dragon's den is a goblet. I don't remember exactly why and as for the last question I'm not really sure what the weak point is in the dwarves plan.\n\nMaybe you should go back and reread those chapters since you know where the answers can be found.  If you think The Hobbit is hard try reading The Lord of the Rings it is a lot harder.\n\nI shouldn't have even answered those questions for you when it is obviously your homework and you will never learn if other people do it for you.