The Father Hunt

Amy DeNovo, Lily Rowan's young assistant, wants Archie to help her find out who her father is. She collars Archie (not Nero Wolfe) in the lobby of Lily Rowan's apartment building and tells him he is the only man she can trust to find her father. She tells Archie that she only has $2000. Archie is interested in the challenge and the plea from an attractive young woman, but he provides her only some hard-earned advice because he is true to his employer and knows Wolfe wouldn't take the case with only $2000 in the pot, and wary of any conflicts of interests.
Before too long, the young woman confronts Wolfe in his den and suddenly flashes enough cash to interest him in finding this man that Denovo never knew and has no record of (even on her birth certificate). To make the task more difficult, she can produce no photographs of either father or mother. We soon find out that the mother has been a recent victim of a hit and run and the case is stumbling from the start.