Carol introduced Elijah and Damon, which went to the party just to met him. When they were talking on a desert room, Damon tried to attack Elijah, but he showed an extreme force, and after call Damon arrogant, he stabbed him with a pencil. He also said he was an Original and told Damon to keep Elena save. Then, he left Damon bleeding.
John caused Alaric asking him if Jenna knew about his extracurricular activities and Alaric answered calling him dick. Then John told him to not sleep at her house anymore, asked his ring back, and left.
Also this is the first episode where John and Alaric meet in the beginning when Jenna and Alaric come downstaris from their "sleepover." This is also the episode when Elijah, Jenna, Damon, Alaric, and Andie have their dinner party when Damon tries to use the dagger John gave him that was dipped in white oak tree ash. You later find out that the dagger would kill Damon if he used it.