Law & Order: Special Victims Unit S16 E07 Chicago Crossover (II)

"Hope in the darkness."

SVU and Chicago PD officer Erin Lindsay try to track down Lindsay's half-brother, who may be able to help take down a child pornography ring. The crossover starts on Chicago Fire S03E07 Nobody Touches Anything (I). It continues on Chicago P.D. S02E07 They'll Have to Go Through Me (III).