When you enter the Sea Bounty in the Athkatla Docks, Baron Ployer, a former slaver, will confront Jaheira and three mages will appear and cast a curse on her, which lowers her dexterity, intelligence and her Charisma by one point immediatly. Also, it will make her weaker every day. Furious about what happened to her and eager to kill him, Jaheira suggests that the party should find Bernard, who may know where Ployer stays.
Enter the government building in the Athkatla Government and ask Corneil about Baron Ployer or the mages. He will not be very helpful.
Speak to Terrece who will be standing just outside the building. He and his associates are not happy with the deal they struck with Ployer and for 1000 gold, they will leave Ployer or for 2000 gold they will agree to kill him. Otherwise, they will still serve the Baron.
Enter Baron Ployer's home in the northeast side of the Slums. If you paid Terrece 2000 gold to kill Ployer, he will appear and do the deed. If you paid him 1000 gold to stay out of it, you can either kill Ployer by himself, or you can force him to remove Jaheira's curse. Jaheira will not honor the deal, however, and will kill Ployer. If you didn't give Terrece anything, you will have to fight Baron Ployer and his three hired mages.
Take the Lock of Jaheira's hair from Ployer's body and Jaheira will feel better. The curse will go away after 24 hours.