Summer discovers the truth about Seth's pot smoking, while Sandy and Matt encounter an obstacle with their hospital project. Meanwhile, Kirsten and Julie take their matchmaking business a little too far, causing Julie to go into hiding. Marissa finally tells Johnny how she truly feels and Kaitlin wonders which "Cooper" Johnny really likes. When Johnny and Kaitlin head to the beach for some partying and drinking, Johnny loses it and finds himself at the edge of reason, and of a 100-foot cliff.