Thefifth-yearresidentsreturnforthefirstdayofayearthatwillmakeorbreaktheircareersMeredithfacestheconsequencesoftamperingwithDerek'sclinicaltrialandisterminatedatthehospital;ApriltriestostepuptotheplateasChiefResidentinthewakeofagiantsinkholeinthemiddleofSeattle;andCristinaandOwenarestillatoddsovertheirdrasticallydifferentfeelingsfortheirunbornchild.