Yes!
it is imposible!
Play as Nina and then go to the stove in the kitchen. Press space when it tells you to. Then, there is a mini game to go through. There you go! Then, you can go throuch the stove or the cellar door in the main hall! Hope it helps!
press a
Okay, so the 6th puzzle piece is hidden in the left corner of the main hall... SIBUNA! (:
you cant
Okay, the relic is at the cellar. You enter under the stove in the kitchen. Once you're at the cellar don't leave 'cause the relic won't be there anymore the second time you go back and you'll have to exit the game and try again. The relic is at the upper rightmost part of the room. Victor is prowling around the table there so watch out and don't get caught. Alright, you're set. Good luck in getting the third relic.
ti is through the doors in the dining room
Well actually its on the roof of the bottom of the stairs on the show but on the game you can not see it.
In the Main Hall
Go in to the kitchen and go to the back and go left
Inside the house.
In Nina's room, look in the chest!