"What brings you to Buenos Aires?"
I'm thinking that "you" is a direct object, but the translation is,:
"¿Qué le trae a Buenos Aires?",
"le" representing an indirect object, as in "to you, or of you".
Where am I losing it here?
You may not be missing anything. Many direct objects in English sentences are treated as indirect objects in Spanish sentences (especially the intransitive sentences like with gustar-like verbs) and especially with people (not objects).
There are certain verbs where Spanish sometimes uses an indirect object where English might use a direct object like llamar when making telephone calls. Where in English we might say "call him" and the him appears to be a d.o., Spanish sees it as "place a call to him" and uses the indirect object.
Another reason could be the regionally accepted leísmo where le is used for lo when referring to single, male direct objects.
I've long since given up trying to decide which is proper in most sentences: le or lo. If it's spoken by a native I assume that he knows what he is doing and as long as you can understand who the pronoun refers to from context.
I am not sure but I think you got confused because the positioning of the "you" and the "le" are different.