Who is Lily Sinclair from Dragon Bones: A Novel and what is their importance?

Lily Sinclair is a representative of Cosgrove's, an auction house. She is passionate and bright, but she uses her knowledge about art and business to mask Chinese artifacts and sell them illegally. Lily pays Brian, an archeology student, to help her in locating and removing artifacts without anyone's knowledge. After he brings her several artifacts of an origin outside Site 518, she knows that he has stumbled on something huge.