I'm not going to spoil it for you.  The clip clocks in at 1 minute and 39 seconds so everybody should be able to find the time to watch it.  I even watched it twice before entering this blog!  At first I was kind of disappointed because I expected something SHOCKING and all I saw was many seconds of water.  I don't think it's going to figure into the plot as prominently as it did in the second episode of Season 1 (aptly titled, "Water") but there's probably 20 seconds devoted to the good old H20 - percentage-wise it might be significant for a clip this short.   I watched the promo a second time, with more patience, and enjoyed the quiet revelation.  Watch it yourself and let me know your thoughts.