Novigrad Dreaming

Novigrad Dreaming is the nineteenth main quest in The Witcher 3: Wild Hunt. Triss Merigold tells Geralt to meet Corinne Tilly, an oneiromancer who might be able to help him locate Ciri.

Quest Description
"Oneiromancers - or dreamers, as they are more commonly called - possess the ability their name inplies to divine the future or relive the past through dreams. Corinne was one of the best of her kind and had no trouble finding clients, even with the hostility to the occult that reigned in Novigrad at the time. Heralt hoped she would spare him a few moments, and set off to find her in a house where she had gone to ply her trade"

—Dandelion

Talk to Rudolf de Jonkheer
Before entering the house, you enter a small cutscene with Rudolf. He gives you some backstory and allows you to go inside.

Find the dreamer in the old house
Upon entering you hear laughter and the sound of footsteps. As you proceed you will hear Corinne Tilly speaking Proceed to the second floor and you will enter a another cutscene where you see Sarah, a godling, standing atop Corinne, who is dreaming. Corinne will tell you to search the attic.

Search the attic
Enter through the door opposite of the bed and then proceed up the ladder into the attic. Smash though the furniture blocking the rest of the attic. Using your Witcher senses, locate the drawing of a crib and the rag doll. Read the drawing of the crib and Geralt will mention placing the doll in the crib which is located on the second floor.

Put the doll in the crib
Head back out the way you entered the attic, go down the ladder and into the small room off to the right side of Corinne Tilly. Place the doll in the crib and you will enter another short cutscene where Geralt hears footsteps followed by the door behind him being slammed shut.

Find Out Why the Door Slammed Shut
Looking at the door, you will see a note with a drawing of an oven. To Geralt's amusement, he deciphers that he now must find an oven.

Examine the Oven
Proceed downstairs and once on the bottom floor, locate the door to the basement, which is right next to the stairs. After you go down the ladder, you will see the oven directly ahead of you. Activate the oven to enter another cutscene. Geralt finally meets the Sarah face to face when she jumps out of the oven in an attempt to scare Geralt. Sarah says she wants to play which is why she put bad dreams in Corinne Tilly's mind and won't allow her to wake up. Sarah explains that she "haunted" the house to scare the banker because she doesn't like bankers and she refuses to leave. Geralt makes a deal with Sarah. He will tell Rudolf that the house is haunted forever and there is no way to lift the curse. In exchange Sarah will stop bothering Corinne Tilly's dreams.

Talk To the Dreamer
Go back up to the second floor and speak to Corinne. Corinne explains how she was attempting to dream the history of the house when she started to be chased by "hungry furniture." Geralt explains that her dreams were tainted by a godling. Corinne asks Geralt if she can do anything for him and he mentions that he is looking for Ciri. She instructs Geralt to meet her at the Golden Sturgeon.

Meet Corinne at the Golden Sturgeon
When you exit the house, Rudolf stops you and asks if you lifted the curse. Either dialogue choice results in Rudolf no longer wanting the house.

Enter the Golden Sturgeon and head upstairs to talk with Corinne. Corinne tells Geralt that she's going to ask questions, and Geralt must answer from his heart. Engage in dialogue with Corinne and tell Corinne as much as you would like. (the more you tell Corinne, the more backstory you get between Geralt and Ciri)

Corinne will eventually ask you who Ciri would have gone to. Either dialogue option will result in Geralt telling Corinne that Ciri probably went to see Dandelion. A cutscene will ensue showing Dandelion, a swallow, and an explosion. Geralt talks to Corinne about his dream and Corinne tells Geralt that Dandelion inherited a brothel called The Rosemary and Thyme.

Closing Quest Description
"Corinne agreed to help Geralt and put together a dreaming seance for him. Geralt has always been an intorvert, and talking about his feelings and loved ones does not come easy for him. Yet that was exactly what the dreamer needed him to do if she was to dream about Ciri. In the end Geralt forced open his shell, then fell asleep - and dreamed. In his dream, he saw Ciri in Novigrad.. With me."

—Dandelion