Skyrim Dark Brotherhood Walkthrough: Whispers in the Dark

This quest starts automatically after the quest Mourning Never Comes. Astrid has a task, of a more personal nature, for you. Ask her what's wrong. She tells you this is concerning Cicero. Ever since he arrived, his behavior's been... well, erratic would be an understatement. She does believe he is truly mad. But it's worse than that. He's taken to locking himself in the Night Mother's chamber, and talking. To someone. In hushed, but frantic tones. Who is he speaking with? What are they planning? Astrid fears treachery.

Your choices are:
Astrid, you're being a bit... paranoid.
By Sithis, we must stop them!
(Remain Silent)

Try the first option, but she says that healthy paranoia has saved this sanctuary before, and her gut's telling her that the demented little fool is up to something. Ask her what she wants you to do. She tells you that she needs you to steal into that chamber, and eavesdrop on their meeting. It'll be no use clinging to the shadows. They'll see you for sure. You need a hiding place, somewhere they'd never thing to look. Like inside the Night Mother's coffin.

You can answer:
But that seems so... disrespectful
Yes, the coffin. It's perfect
(Remain Silent)

If you suggest that hiding inside the Night Mother coffin is disrespectful, she says that you have no other choice. You need to remain unseen. She wants you to go and hurry before they meet. And report back to her with whatever you learn.

Open your quest journal:

Whispers in the Dark
Astrid has heard Cicero speaking with someone, in whispered tones, in the chamber of the Night Mother. She fears they're conspiring against the Sanctuary, and wants me to eavesdrop on the conversation. I'm to sneak into the chamber, and hide in the coffin of the Night Mother.

Follow the quest marker to the room where the Night Mother's coffin is, them pick the lock of the coffin (Novice Lock) and hid in there. You now need to eavesdrop on Cicero.

Cicero: Are we alone? Yes.. yes... alone. Sweet solitude. No one will hear us, disturb us. Everything is going according to plan. The others... I've spoken to them. And they're coming around, I know it. The wizard, Festus, Krex... perhaps even the Argonian, and the un-child... What about you? Have you... have you spoken to anyone? No, of course not. I do the talking, the stalking, the seeing and saying! And what do you do? Nothing! Not... not that I'm angry! No, never! Cicero understands. Heh. Cicero always understands! And obeys! You will talk when you're ready, won't you? Sweet Night Mother.

Suddenly the Night Mother Glows. You hear her voice: Poor Cicero. Dear Cicero. Such a humble servant. But he will never hear my voice. For he is not the Listener.

You hear Cicero talking again: Oh, but how can I defend you? How can I exert your will? If you will not speak? To anyone!

Again, you hear the Night Mother, who tells you she will speak to you, for you are the one. You who shares her iron tomb and warms hair ancient bones. She gives you  a task - to journey to Volunruud and speak with Amaund Motierre.

Cicero keeps whining about failing the Night Mother, trying hard to find a listener to her. The night mother asks you to tell Cicero the time has come. Telll him the words he has been waiting for, all these years: "Darkness rises when silence dies".

The coffin door suddenly opens! Cicero sees you and accuses you of being a treacherous debaser and defiler. You have violated the sanctity of the Night Mother's coffin. He asks that you explain yourself. Talk to Cicero.  Tell him how the Night Mother spoke to you and told you that you were the one. But Cicero does not believe you, he thinks you are using trickery and deceit, because the Night Mother speaks only to the Listener. Tell Cicero the words that the Night Mother instructed you to tell, "Darkness rises when silence dies". Cicero says those are the words, the Binding words. Written in the Keeping Tomes. The signal so he would know. Mother's only way of talking to sweet Cicero. Cicero finally realizes that the Night Mother is back and she has chosen you as her Listener.

Astrid enters the room to see what's the commotion. She is aggressive towards Cicero but he updates her about the listener. The Night Mother has spoken. The silence has been broken. The listener has been chosen!

Speak to Astrid. When she heard Cicero screaming, she knew that you had been discovered. She feared the worst. She asks you if you are alright. Tell her you are fine. Tell her Cicero was just talking to the Night's Mother, not to an accomplice. And the Night Mother spoke to you. Tell Astrid about the mission to speak to someone named Amaund Motierre in Volunruud. She has no idea who Amaund is, but she knows where Volunruud is. Ask Astrid if you should go to Volunruud to talk to that man. She objects. She does not know what is going on here, but you take orders from her. She is still the leader of this family and does not like the thought of her authority so easily dismissed by the Night Mother. She needs time to think about this. She wants you to go see Nazir and do some work for him. Astrid will find you when you are ready to discuss the matter further.

Go speak to Nazir and tell him Astrid sent you for some additional work. He has some additional contracts for you, usually random - for example he can ask you to kill  an Orc Bard named Lurbuk, or a Vampire by the name of Hern. Go and perform the two contract kills in order to advance to the next quest in the Dark Brotherhood series.

This concludes the quest, Whispers in the Dark.