Zhentarim intrigue, Possible benefactor?

Running SKT for my troupe, PCs just got finished with Goldenfields,

End of last session I waved some sidequests at them and they decided they want to escort a Zhent spy to Bargewright so he can report to his superiors.

I have plenty of content for Womford, I plan on running them through Banquet of the Damned.

Before visiting Womford however they will go to the Bargewright Inn and I was wondering how I should best go about setting up a hook for the PCs to get caught up in Zhent affairs.

This will be the first major faction to potentially recruit them and I love the idea that they agree to help the Zhent now only to regret it after being approached by a Harper once they are in too deep.

any brainstorming or ideas would be appreciated.

Thanks!