The Hills Season 6 Episode 4 (The Hills s06e04) with title “Desperate For Help” airs on Tuesday, May 18th 2010 at 10:00 pm via MTV.
Here is summary for The Hills Season 6 Episode 4 :

Spencer and Heidi’s erratic behavior forces their friends and family to make a difficult decision. Meanwhile, Kristin and Brody take their relationship to the next level. Elsewhere Audrina is stood up by Ryan.

Few hours after original series aired on TV, online streaming video for The Hills Season 6 Episode 4 usually available on Net and of course, if video available, as soon as possible will show you where you can watch this episode for free.