“This Is Our Youth” provides a 48 hour window into the lives of three lost souls as they step out from adolescence and plunge into adulthood. Set against the backdrop of New York City in the early 1980’s, meet Warren Straub, who steals $15,000 from his tycoon father; Jessica Goldman, the young woman Dennis yearns for, and Dennis Ziegler, Warren’s magnetic and drug-dealing friend.