Regi Davis

All reassess their personal lives after witnessing a chance reunion between two long-lost lovers in the emergency room; Karev treats a troubled teen; Meredith shares her suspicions with Cristina.

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.

With Gideon missing and Hotch and Prentiss off the team, the BAU tackle one of their trickiest cases, a Milwaukee serial killer who uses his son as bait to ensnare women in broad daylight.

Lilly won't let Miley pay for her class trip to Washington, and has a sale instead. She's angry when Miley pays people to buy stuff.

When a government witness is murdered, the FBI hires Cal and co to determine who was responsible for leaking the victim's whereabouts. The team are also tasked with keeping Agent Reynolds, who is key to closing the case, out of harm's way. However, suspicions are aroused when Reynolds refuses to testify.

Beckett is asked to assist with a narcotics investigation and faces dangerous men from the New York underworld.