Kyle XY: Endgame (season finale)
We're promised that this episode will answer the question: "who is Kyle XY?" (Spoilers after the jump.)
Well clearly, DNA results faked or not, there's something else here besides Kyle being Noah the long lost son of the Peterson couple. A cut-away to the "company" whose operatives continue to order each other to kill Kyle (or 781227 as they dispassionately term him) and erase all evidence of his existence, reminds us of that.
After Foss helps Kyle remember what happened that one fateful night, Kyle decides the only prudent action is to pretend he remembers the Peterson couple and to go with them, in order the remove the Trager family from any potential dangers. Kyle takes a quick time-out to dispense life-lessons to his angst-ridden teen friends. Amid heartfelt goodbyes for the Trager family and the others whom Kyle has befriended, Declan remains suspicious, and feels somewhat betrayed by Kyle's seeming unwillingness to let him in on what is really going on. But Kyle trusts him more than he knows.
The Peterson couple are not who they seem to be, but even more than that, they are not who they seem to seem to be. Kyle is taken to Adam and gets his answers, but they will hardly put him at ease. The explanation Foss reveals to Kyle for his amnesia is the simplest one possible -- but one Kyle himself would have never imagined.
In the season's cliffhanger final shot, we are back in the company's secret lair and get to see what is in that glass chamber they've been hovering over. 781228 -- that's a big number.