Izzie's medical condition requires a difficult surgery; one of Owen's PTSD episodes causes Cristina to be injured.
Stillman asks Rush and Valens to reopen the 1980 case of an 8-year-old boy found buried in a snowdrift.
Castle finds himself vying with an FBI agent for Beckett's attention when she is called in to help the agency investigate a little girl's disappearance from her home.
As the presidential investigation intensifies, Bartlet recalls the circumstances surrounding his decision not to disclose his multiple sclerosis.
While aboard a runabout shuttle he has stolen from DS9, Chief O'Brien records a log recounting how he returned from a mission to find his wife and friends had inexplicably turned against him.