When Elliot's engagement ring doesn't fit, she feels that the perfect proposal she's always dreamed of is ruined and takes back her yes. To make up for it, Keith lets her plan her dream proposal; Elliot's visiting sorority sister, Melody (guest star Keri Russell), continues to spurn J.D.'s advances; Carla's still not emotionally ready to have sex after having a baby, driving Turk over the edge; J.D. has an epiphany.