For any type of Treasure Trail activity, you will need to carry the Clue scroll. If you die and lose the clue, then you cannot get it back. You will have to try to get another one. You can only have one clue at a time, either in your bank or inventory. For Coordinate clues, ...
However, the Dagannoth Kings fight pits you against these three kings all at once. To make matters worse, all of them are at level 303. Without a proper strategy guide and preparation, the fight against the DKs is arguably one of the toughest fights in the game right now. Before anything...