Check out this Skyrim Dark Brotherhood walkthrough. Part 11: The Cure for Madness.
Astrid: She’s right. I’ll be forever in your debt, dearest brother. Now be be quiet. Just…just rest.
Male Voice: Feel better, lizard bro. We got a crazy to track down. That’s not his room.
Astrid: Have you found something? Good, good. Does it say where he may be headed? The Dawnstar Sanctuary? Whatever for? Never mind, it doesn’t matter. You need to leave. Now. Every moment counts, so I want you to take my horse. His name is Shadowmere. You’ll find him outside, by the pool. Let’s just say he’s…one of us. Find Arnbjorn. Make sure my husband’s all right. And then, send that jester’s twisted little soul to the Void, in as many pieces as possible. I took that prancing fool into my home and this is how he repays me?
Male Voice: Looks like we get a new ride. Nice. All right, buddy. We ride. Arnbjorn chased Cicero toward Dawnstar, so that’s where we’re headed. I’ll loop around the town, this way. There he is.
Arnbjorn: Should have figured Astrid would send you. What gave it away? Yeah, got to admit that little jester is good with that butter knife. But don’t worry, I gave as good as I got. In there! Through the door. Some old Sanctuary, by the looks of it. I would have followed him, but I don’t know the phrase. All right, you convinced me. Doubt I’d be much good to you, anyway. The little fop cut me pretty deep. But I slashed him good. Pretty sure I severed an artery. Don’t know what you’re going to find in there…but you can probably just follow the blood.
Male voice: The pass phrase is found here, in Cicero’s journal. “What is life’s greatest illusion?” And the answer, “Innocence, my brother.”
Ghost Voice: What is life’s greatest illusion?
Male voice: Innocence, bro.
Ghost voice: Welcome home.
Male voice: All right, Cicero.
Cicero: Listener! Is that you? Oh, I knew you’d come. Send the best to defeat the best. Astrid knew her stupid wolf couldn’t slay sly Cicero.
Male voice: Oh, god. Are these his clothes? Don’t tell me he’s naked somewhere in here. Cicero, I swear, if you’re naked in here, I’m gonna stab you. Great, we got ghosts. Just what I needed.
Cicero: Oh, but this isn’t at all what Mother would want. You kill the Keeper or I kill the Listener? Now that’s madness.
Male voice: All right, we’ve got Whirlwind Sprint equipped. And, across.
Cicero: Ouch! Pointy pointy! My home is well defended. I always have been a stickler for details. Get it? “Stick-ler.” Oh, I slay me!
Male voice: Oil on the ground. What’s going on here? That was fortunate. That was a totally intentional distraction, over his shoulder. Got some skill books there.
Cicero: You’re…still alive. Cicero respects the Listener’s abilities, of course, but could you at least slow down a bit? I’m not what I used to be.
Male voice: They are right on top of me. So, I’m going to Unrelenting Force.
Sanctuary guardian: You can’t kill what’s already dead, mortal.
Male voice: That was a close one. I kept hitting the button, but the shout wasn’t going off, for some reason. What’s in the creepy cavern?
Cicero: Chilly! You’ll enjoy this. Not an original part of the Sanctuary, per se. Let’s call it a “forced addition”. Forced by what? Oh, come and see!
Male voice: Oh, great. A troll. It has a name.