▁drawn ▁towards ▁Dan ▁and ▁inv ites ▁her ▁to ▁come ▁with ▁him ▁to ▁Argentina , ▁which ▁she ▁accepts . ▁Upon ▁their ▁return , ▁Ser ena ▁breaks ▁up ▁with ▁A aron , ▁and ▁she ▁is ▁free ▁to ▁purs ue ▁a ▁relationship ▁with ▁Dan . ▁The ▁two ▁reun ite , ▁only ▁to ▁face ▁the ▁awk ward ▁discovery ▁that ▁they ▁share ▁a ▁sib ling . ▁Dan ▁and ▁Ser ena ' s ▁relationship ▁further ▁suff ers ▁when ▁she ▁real izes ▁their ▁diver ging ▁college ▁choices , ▁her ▁continuous ▁m istr ust ▁in ▁him , ▁and ▁Dan ' s ▁affair ▁with ▁a ▁teacher ▁that ▁drives ▁her ▁to ▁prem ature ly ▁end ▁their ▁relationship . ▁ ▁After ▁throwing ▁a ▁dis astr ous ▁S weet ▁Six teen ▁party ▁for ▁Jen ny , ▁Ser ena ▁retre ats ▁to ▁Spain ▁with ▁Po ppy ▁and ▁Po ppy ' s ▁boy friend , ▁Gabriel ▁Edwards . ▁She ▁returns ▁to ▁New ▁York ▁purs ued ▁by ▁Gabriel ▁after ▁he ▁broke ▁up ▁with ▁Po ppy ▁and ▁finds ▁herself ▁in ▁a ▁new ▁relationship . ▁During ▁a ▁party ▁held ▁by ▁her ▁mother , ▁Ser ena ▁disco vers ▁that ▁Gabriel ▁and ▁Po ppy ▁have ▁con ned ▁her ▁mother ' s ▁guests ▁and ▁calls ▁on ▁Bla ir ' s ▁aid ▁to ▁obtain ▁their ▁st olen ▁money , ▁breaking ▁up ▁with ▁Gabriel ▁as ▁she ▁purs ues ▁Po ppy . ▁Bla ir ▁rel uct antly ▁teams ▁up ▁with ▁Ch uck ▁and ▁a ▁reform ed ▁Georg ina , ▁ign oring ▁L ily ' s ▁wishes ▁that ▁they ▁let ▁her ▁handle ▁it ▁herself , ▁ending ▁with