Sharon Marquette is one of DC's finest madams and a client of Olivia Pope. AUSA David Rosen is after Sharon's client list, which is a who's who list of Washington heavyweights and she doesn't want to give it up because many families could be destroyed. She is later helped when Olivia assembles a number of those high profile clients explaining what's at risk if the US Attorney's office gets their hands on the list. David's bosses tell him to stop his investigation.
Side note: Sharon's client list includes one of Olivia Pope & Associates very own... Stephen Finch!