Two women are found dead in an apartment building water tank, both with their faces slashed. The slashes were caused by two different blades.
Both women were prostitutes, possibly drug addicts or former addicts. Both had their hair dyed.
An Unsub "saves" a woman named Danielle from being hurt on the street. He offers her a ride in his van. He opens up the back and she sees the arm of a dead girl peeking out from under some tarp.
The Unsub chloroforms her and kidnaps her.
The body of a third victim shows up in a covered jacuzzi. This woman's face was also slashed. A suture was left behind.
Garcia discovers that the women were in rehab.
Danielle wakes up, after having her face slashed and wrapped in gauze.
The M.E. discovers that the women had pain medications in their blood streams. As if the Unsub was trying to make them feel better after he cut them. The third victim had a saline implant in her cheek.
The Unsub gives Danielle some medications. He removes the bandaging from her face. She looks into the mirror and sees that she's horribly disfigured.
The BAU realizes that the Unsub is trying to re-create a woman he was in love with, a woman who was disfigured in real life. This is why he's been disfiguring his victims.
The Unsub puts a dress on Danielle.
Garcia discovers "patient zero" - the woman the Unsub has been trying to recreate. Her name is Sarah Sherwood. She suffered from a facial deformity. She drowned herself at her parents' house three weeks ago, about the time the first victim went missing.
Garcia discovers the name of the Unsub. He's Joseph Berzon. Garcia tells the team Berzon was the one who discovered his girlfriend Sarah's body in the pool.
Berzon knew his victims from working for a food delivery service that delivers to the rehab center.
Berzon - the Unsub - leads Danielle to a bedroom that is filled with pictures of Sarah. He kisses her.
Danielle plays along, pretending to be Sarah. She picks up a hand mirror and hits him with it. She rushes outside. She stops a jogger but Berzon tells him she's okay, and that she just got out of the hospital.
He brings her back inside and puts her on the bed.
Rossi and JJ rush into bedroom. They tell him to get away from Danielle, and that she's not Sarah, and never was.
JJ arrests him.