Into the Dead City is a main quest in sword coast legends. You can start it after talking to Soronil in the Market district of Luskan. To complete it you need to find four items: Black Candle, Crystal Jar, Grave Dust and Ogre Zombie's Tooth. You can get them from one of residences, in the cemetery and in the catacombs (M5,Slums). After you have all the items go to the Mage Maferil's hideout in the slums.
When n-Space set out to make Sword Coast Legends, they wanted to capture the spirit of classic CRPGs like Baldur's Gate and Neverwinter Nights. They succeeded, and it's clear that they've taken the best of what those games offered and added some of their own flavor to the mix. Gameplay elements like tactical time pausing, using different characters to perform out of combat actions like searching for traps doors, and how in combat spells aren't spammable give everything a Dungeons & Dragons feel that's respectful of the game's RPG predecessors.
Another key element of those classic CRPGs was the use of companions to help the player on their adventure. Sword Coast Legends features five formidable and memorable companions: Bryn Lightfingers, Hommet Shaw, Illydia Maethellyn, Jarhild Stoneforge, and Larethar Gulfrin.
The lands of the Sword Coast are home to the cities of Baldur's Gate, Waterdeep and Neverwinter Nights, as well as a variety of legendary locales. The Sword Coast Adventurer's Guide offers D&D fans a wealth of detail on the places, cultures and deities of northwestern Faerun.