Chaos ensues when the residents find themselves in charge of the hospital during a night shift.
J.D. and Dr. Cox react differently to the news of Ben's illness. Turk learns he is the number two intern. Elliot gets an opportunity to critique Dr. Kelso's work.
J.D.'s brief experience with the popular crowd distances himself from his best friend. Elliot and Paul's relationship may be progressing to the next level. Dr. Cox and Dr. Kelso play ruthless pranks on each other.
While Turk waits for Carla's answer, his visiting brother reveals news about his own marriage. Dr. Kelso's colleague and friend has to face the end of his career and Dr. Cox and Jordan disagree over learning the sex of the baby.
The wedding day finally arrives for Turk and Carla, but they soon discover that all the planning in the world could not prepare them for the day that lay ahead. Meanwhile, JD struggles to mend his relationship with Elliot.