Thefifth-yearresidentsreturnforthefirstdayofayearthatwillmakeorbreaktheircareers:MeredithfacestheconsequencesoftamperingwithDerek'sclinicaltrialandisterminatedatthehospital;ApriltriestostepuptotheplateasChiefResidentinthewakeofagiantsinkholeinthemiddleofSeattle;andCristinaandOwenarestillatoddsovertheirdrasticallydifferentfeelingsfortheir unbornchild.