Frasier's vacation plans with Claire turn disastrous when Daphne, Niles and Martin show up at the same resort and Frasier starts dreaming about Lana.
With Gideon missing, and Hotch and Prentiss off the team, the BAU investigates one of its most difficult cases yet as the remaining agents track a serial killer in Milwaukee who abducts women in public places by using his son as bait.
Beckett is asked to assist with a narcotics investigation; when a routine undercover operation goes awry, Beckett is faced with dangerous men from the New York underworld.
Izzie continues helping to plan Derek and Meredith's wedding in spite of her cancer treatments; things don't go smoothly when Callie introduces Arizona to her father; Owen seeks out help for his post-traumatic stress disorder.
Mike and Carl's annual pilgrimage to the Chicago Cubs' Opening Day is interrupted when Molly comes along.