Regi Davis

Prentiss resigns, Hotch requests a transfer and Gideon goes missing, leaving the team three members short as they hunt a serial killer in Milwaukee, who kidnaps women from public places.

While undergoing aggressive cancer treatment, Izzie focuses on planning Meredith and Derek's wedding; Callie's father visits; Owen seeks help with his PTSD.

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.

McGarrett and the team try to determine what happened when Grace gets into a life-threatening car accident; Tani helps Koa when his rehab patient goes missing.

Gibbs and McGee travel to Russia to safely escort home an NCIS computer engineer connected to classified intel, but their mission is compromised, and they are forced to go off the grid while hunted by a Russian mercenary group.

Lightman's team investigates the murder of a government-protected witness, which unearths dangerous secrets about Reynolds; Lightman puts himself at risk to save Reynolds' career and life.