At the party, Frank Smith surprises Mordecai by choosing him for a special guest seat on the 1,000th flight—a spot coveted by Frank’s ambitious co-worker, Jackie Carmichael . The Climax and "Downer Ending"
Mordecai is hesitant to attend because his girlfriend, CJ, cannot make it due to a river-cleaning volunteer commitment. He fears the awkwardness of being at Margaret’s parents' house without CJ, especially since he and Margaret have a complicated history. [S6E20] 1000th Chopper Flight Party
As the helicopter takes off, Mordecai tries to get CJ's attention. In the process, he accidentally trips and falls into Margaret’s lap. From the ground, CJ sees this and assumes they are cheating. At the party, Frank Smith surprises Mordecai by
CJ finishes her volunteer work early and decides to surprise Mordecai at the party. As the helicopter takes off, Mordecai tries to
The episode is best known for its dramatic conclusion, which TV Tropes characterizes as a "downer ending":
The episode centers on an invitation sent to Mordecai and Rigby for a party celebrating the of Frank Smith (Margaret’s father) as the pilot of Chopper 6.