Kids say the darnedest things: find out what happened when Julianna Margulies' 3 year-old son saw her getting dressed. Joe Wong performs stand-up on the "Late Show" on September 1, 2011.

Louie waits at Grand Central Station to pick up his sister and niece for a visit. However, his sister surprises him by dumping the niece Amy on him and running off to catch a train to Philadelphia. Louie and Amy spend the night in New York together, visiting an indie rock club at her request, after which she asks to see Louie perform. After seeing her enamored with Godfrey's set, Louie attempts, unsuccessfully, to impress his niece by doing crowd work. After the set, Louie is surprised to see Godfrey spark up a lively conversation with the usually sullen teen. When they arrive back at the apartment, Louie receives a call from a Philadelphia hospital informing him that Amy's mother was found "acting irrationally" in a public fountain and that she is being held under observation. With Amy's father out of the picture, Louie volunteers to keep Amy until his sister is released.

When Traci and Andy are sent out on an undercover training exercise, they stumble upon a young woman who is about to die of an overdose. Meanwhile, Dov finds himself on a “ride-along” with a drug dealer and old friend of his deceased brother. Back at the station, Chris and Gail deal with a teenage boy they found tied up at a graveyard; sifting through the wreckage of their relationship, to try to get to the bottom of a bullying situation.

Harvey's former mentor turns to him for help when his office comes under investigation. Meanwhile, Jenny suspects Mike may be occupied with more than just his job.

Recapping key characters and storylines from the show's first two seasons; includes interviews with stars Julianna Margulies, Christine Baranski, Josh Charles, Archi Panjabi, Matt Czuchry, Alan Cumming and Chris Noth.

guest tonight are Kathy Griffin, Lynette Rice and musical guest Lenka.