Avernus—The Nine Hells—what's not to love? This module will take your party from Level 1 to ~ Level 13. Staring in Baldur's Gate and transitioning into Avernus, the sway of the Evil Gods is looking to envelope to mostly (somewhat) good denizens of Baldur's Gate within the evil cloak on the Nine Hells. Is there anything that can be done? You bet there is.
The book also includes a significant appendix on Baldur's Gate—a major city on the Sword Coast, with enough going on to get even the most Lawful Good in your party in trouble.