In Los Angeles County, a dense labyrinth of cities and neighborhoods covers more than 4,000 square miles. The area is home to 9.9 million people (2.5 million children) -- and has the largest foster care system in the country.
Lisa Ling explores this foster care system and the children in it on Thursday's episode of "Our America." Within the first few minutes of the episode, Ling accompanies a veteran social worker named VaSonne to investigate a claim of a child in danger.
"What do we know about this case?" Ling asks in the above clip.
"The mother was spotted at a restaurant under the influence of some type of substance and was driving with her 10-month-old child," VaSonne tells her.
The two arrive at the Culver City Police Station, where the mother and her daughter, Lily, have been taken into custody. VaSonne goes inside while Ling waits on the curb.
Over the course of her 11-year career as an emergency response worker, VaSonne has removed hundreds of children from dangerous homes. The decision to separate a child from the parent is never an easy one, however, and as Ling waits, darkness falls on the city.
Inside, Ling says, VaSonne is likely speaking with the mother and trying to determine if any nearby relatives can take Lily. "If not, there's a very good chance that VaSonne will be leaving this police station with a baby in her arms," Ling says.
After a while, VaSonne emerges.
She isn't alone.
Baby Lily will be taken to the Department of Children and Family Services welcome center, the first stop for young children entering the system. Ling follows her story -- along with those of other children, families and foster parents within the system -- on the next episode of "Our America."
"Our America with Lisa Ling" airs Thursdays at 10 p.m. ET on OWN.