Bailee Madison on 'Law & Order: SVU' TONIGHT!

Bailee Madison situates herself in a window seat in this new still from Law & Order: SVU.

The 10-year-old actress plays MacKenzie Burton in tonight’s episode, “Locum.”

In “Locum,” a foster couple (Joan Cusack, Peter Strauss) call Detectives Benson (Mariska Hargitay) and Stabler (Christopher Meloni) to the scene of the crime when their ten-year-old adopted daughter disappears.

It soon comes to light that she ran away to meet with a man named Erik Weber (Henry Ian Cusick), whom she met on the internet and whom Benson and Stabler suspect of ulterior motives regarding the girl. Weber denies any wrongdoing, and also expresses romantic interest in Benson. However, as the investigation continues, the detectives realize that the girl’s foster parents may be hiding something that could change the entire course of the case.

“Locum” premieres TONIGHT, September 22 @ 9PM ET/PT on NBC.