Slaver's End

From the introduction:

Phlegos Dulm is a traitor to the Pathfinders. Society agents obtained evidence that the disgraced former venture-captain was sabotaging the monetary and political power of his rival Venture-Captain Wulessa Yuul (Pathfinder Society Scenario 10-06: Treason's Chains). He has poisoned his enemies, including Pathfinders and their allies, and profited heavily from his direct involvement in illegal slave trade. After Phlegos attempted to poison a trio of agents at Venture-Captain Roderus’s retirement party, Roderus turned over all his influence and responsibilities to Wulessa, but not before tasking her with tracking down the renegade half-orc and returning him to the Society for judgment.