The Dark Urge: Act 2
This page will contain spoilers for the Baldur's Gate series, especially baldur's gate 3 which is owned by Larian Studios
So the party when entering act 2 can do many things, but the first thing that happens is Gale, who is one of the possible companions, will meet an elderly wizard named Elminster, who is a living legend in the forgotten realms, (Name of the world in setting) will say that the goddess of magic told him, to tell Gale to detonate a thing he has in his chest at a place called Moonrise Towers, (which is the party's objective) and put an end to the absolute.
If the party makes their way to this giant dome of light in the distance they will meet Harpers (Basically people who decided that to help people they would take a creed and travel while slaying monsters without taking pay to help the world) and if they keep going they will arrive at the dome of light and meet Jaheira, the current leader of the harpers, who was a main character back from the 1st and 2nd Baldur's Gate games, she will restrain the party when they enter, because she can tell that they are infected, and talk to them. After chatting with Jaheira without making her hostile, the party can explore the Last Light Inn which is what the area in the dome of light is called, within that dome of light is Isobel, a cleric of Selune who keeps the dome of light, which is a protective barrier, around the Inn. After meeting isobel the Dark Urge will be met by Sceleritas Fel, a goblin looking creature, at camp who wants them to kill Isobel for a gift from the Dark Urge's father, the god of murder, Bhaal. If the party does this, the barrier breaks, and almost everybody in it, excluding the party, Jaheira, and a handful of harpers will die.