by GregF
You'll be told when to remove it. Page 6:BACK IN BOX AND THE TOMB
If you are told to return a game component to the box, it will not be part of the current game but should return to use in the next game. For example, you may be told to return an Item card to the box. That Item is gone for this game. At the end of the game, put it back into the Item deck.
The Tomb is where you store cards that will remain out of play until you are told to return them. In some cases, this may be after you have finished the campaign or it may be the next game. When you are told to put something in the Tomb, put it under the tray in the game box.
If you are told to return a game component to the box, it will not be part of the current game but should return to use in the next game. For example, you may be told to return an Item card to the box. That Item is gone for this game. At the end of the game, put it back into the Item deck.
The Tomb is where you store cards that will remain out of play until you are told to return them. In some cases, this may be after you have finished the campaign or it may be the next game. When you are told to put something in the Tomb, put it under the tray in the game box.