AcquisitionEditAfter returning from the Underdark, you must go to the Graveyard District to confront Bodhi in her lair. Upon entering the Graveyard, Bodhi appears with several vampires. After a quick chat, Bodhi abducts your romanced NPC and makes off with him/her, leaving you one party member short and giving your party all of the abducted NPC's equipment. Fight the vampires and enter the tombs. Fight your way through there and go to the lower tombs. There, you will discover Bodhi's lair and your lover, who has been turned into a vampire! Sadly, you will have to kill him/her along with all the other vampires, creatures and Bodhi. But don't worry! All is not lost!
Resurrecting Your LoverEditUnfortunately, the resurrection spell does not work here, so you must pick up your lover's body. Then, stake Bodhi and retrieve Bodhi's black heart. Search the rooms of Bodhi's lair and you will find a trapped chest. Open it and there will be some books that will tell you how to bring the romanced NPC back to life. Either read them to figure it out on your own or read on for a detailed explanation.
In short, you must travel to the Temple Ruins in the Umar Hills with your lover's body and Bodhi's black heart. Make your way across the lettered tiles and into the room with the big statue. Place your lover's body and Bodhi's black heart on the pedestal, and your lover will be restored to life! S/he will profusely thank you and will ask to rejoin the party.
And that's it! All that work for no experience points or gold. The things we do for love!