A Riddle In The Dark

Erestor did not need a candle.  He knew every step, every inch of the cellars, and could put his hand on anything required even in total darkness.  But as he neared the foot of the stairs he suddenly stepped into unexpected water.

Standing quite still, he reached out and took matches and a candle from a shelf.   The flame reflected off dark water, for the cellar had unaccountably become an underground lake.  Barrels and casks floated here and there, and water dripped in the distance.

He stared in disbelief, then turned and bellowed up the stairs. 

“Elladan!  Elrohir!  Come here!”