Hard Answers

It is received right after the completion of the quest "Speaking With Silence."

Objectives

 * Speak with Enthir.
 * Speak with Calcelmo inside the Understone Keep in Markarth.
 * Gain Entry to Calcelmo's Museum.
 * (Optional) Obtain key to Calcelmo's Museum.
 * Find Calcelmo's Falmer Translating Guide.
 * Duplicate the writing on Calcelmo's Stone with charcoal and a paper roll.
 * Return to Enthir.
 * Speak to Karliah.

Walkthrough
First, the Dragonborn must speak to Enthir, who can usually be found at The Frozen Hearth in Winterhold or in the College of Winterhold. After the conversation with him, they must travel to Markarth and speak to Calcelmo at Understone Keep—he will not grant them access to his research unless persuaded, bribed, intimidated or if they have helped him out by completing the temple quest "The Book of Love," the Dragonborn has completed the side quest to kill the spider Nimhe in the excavation site, or just simply sold him any piece of Dwemer equipment that he requested. It can also be pickpocketed from him.

Calcelmo's Museum
Once the key to Calcelmo's Museum is obtained, head to the North wing of Understone Keep and enter the Museum. If Nimhe has not been killed, the guard at the door will tell the Dragonborn that they are not allowed to go in, after the dialogue the guard will allow entrance into the museum. After entering the museum, the guards will not be hostile if Calcelmo's quest is completed, or if he was bribed, intimidated, or persuaded. However, if the key was obtained by stealing, the guards will be hostile, which forces them to sneak past or kill the guards, also, watch out for the guard in the center.

In this first area there are many common Dwemer artifacts that are directly on display or are in display cases. There are also display cases with expert difficulty locks further into the room that contain weapons, and there are a couple of bookcases with adept difficulty locks with books. A Stone of Barenziah is in the room behind the gate to the left as the Dragonborn enters. In this same room is a chest with an expert level lock with valuable items.

Calcelmo's Laboratory
After getting past the guards, head up to Calcelmo's Laboratory, a restricted area protected by Calcelmo's personal mercenaries called Wizard's Guards, who will attack on sight. In the laboratory, in an area to the left, there is a journal and Spider Control Rod. After a few moments there will be a guard that will walk through the other two doorways opening them up. These guards can be killed with no bounty, a task that can be aided with Aicantar's Spider by using the control rod. The doorway on the left is barred so the right path is the only path available. In order to proceed they must pick the master lock or use Calcelmo's key making the lock open effortlessly. Two guards will be talking and eventually travel down a hallway. Either follow the guards and sneak by to get to the staircase to the next area, or go to the opposite path and get to the stairway.

Going the opposite way of the guards will lead to a hallway filled with a gas that is highly lethal and quickly drains health. Opposite to the hallway there is a button that if stepped on will clear the path, however one needs to run through before the gas fills the room again. An object (such as the nearby Markarth guard's body) can be left on top of the button to remove the gas. There are also gas disabling buttons on the sides of the passage, those may be utilized to get "safe spots" for healing. Note that the guards above would probably notice this.

Note: Poison resistance does not grant immunity to the damage from the gas. However the Argonian Histskin power can completely negate it. Vampires, too, are immune to the gas.

Alternatively, there is valve on a column near where the two guards walk. Turning the valve activates a spinning blade trap which can be used to kill the guards, while going completely unnoticed (it is on the side of a stone pillar facing away from the patrolling guards a little above a lit lantern) alongside the merceneries the final section will contain Calcelmo's nephew, Aicantar sitting on a chair in front of a table. At the end of the floor is a valve that can be activated. An explosion will happen that will make Aicantar flee and make it possible to pass through and head up to the tower. The explosion can be timed so that the patrolling guard doesn't die. If guards in the previous room are still alive, they will also run through this room. Continue along through the next couple of doorways to the door leading to the wizard's balcony. In the room before the balcony there is a larceny target called the Dwemer Puzzle Cube, which may be taken to Delvin Mallory for leveled gold. On another table there is a chest with valuable loot, plus the enchanting book Twin Secrets.

Calcelmo's Tower
In order to proceed, follow the balcony up and to the right and enter Calcelmo's Tower, and head up to Calcelmo's Stone. To copy Calcelmo's research on Falmer, one needs to get a roll of paper and a charcoal, which are found in abundance in the room before reaching the stone tablet, before activating the stone. There is also a copy of Chimarvamidium (Heavy Armor skill book) on one of the tables. Once the Dragonborn makes the rubbing, Aicantar, two wizard guards (or three  wizards without Aicantar) and Captain Aquilius will enter the tower. Aicantar insists that somebody is trying to steal his uncle's research, and demands that the merceneries search the tower from top to bottom. If Aicantar is missing (killed by the Dragonborn) then Captain Aquilius will start dialogue suggesting that he and the other guards are just relaxing and taking a break.

With a high enough magicka and illusion, it's possible for the Dragonborn to neutralize all four hostiles using one or two pacify area spells. Alternatively, it is possible to just sneak past the guards and reach the door to the balcony. Once the guards are dealt with, they can either walk out the door and slide down the waterfall (directly to the right after the stairs) or retrace their steps back to the room previous to the balcony, then take a right (the door to the room needs to be unbarred). This room will lead to the starting chamber of Calcelmo's Laboratory, allowing them to return to the Museum. Killing the guards and Calcelmo's nephew seems to only occasionally incur a bounty.

Frozen Hearth
Once the Dragonborn has left the Understone Keep, the objective marker will automatically update to the Frozen Hearth's cellar in Winterhold. Returning and speaking to Enthir and Karliah at the Frozen Hearth's cellar in Winterhold will complete the quest.

Rewards

 * Nightingale Blade, from Karliah, previously owned by Gallus Desidenius

Trivia
Wizard's Guard "Are you serious?" Aicantar "You heard me. Kill any intruders on sight. We cannot have our work interfered with."
 * This is one of the few Thieves Guild quests in which it is allowed to kill an enemy to complete it.
 * An aid to sneaking through Calcelmo's Laboratory is to use the various traps in the area. If used properly, all guards can be neutralized without getting a bounty.
 * The shout Throw Voice in combination with sneaking can prove useful if the Dragonborn chooses not to eliminate the guards.
 * To avoid almost all confrontations within Calcelmo's Laboratory, the Dragonborn can repeatedly try to activate near the edge of the barred door to the left of the entrance. If done correctly, with luck, it will remove the bar and open the door allowing access opposite the puzzle cube, with the door to the wizard's balcony just to the left.
 * Enthir becomes a guild fence, if the Dragonborn is not already a member of the College of Winterhold, in which case he is automatically a fence.
 * Once the quest is complete, immediately upon exiting Calcelmo's Tower, there is a narrow path leading to Markarth’s waterfall. There are two skeletons and two Septims at the bottom. This also may be referenced by some of the guards saying "Don't trip."
 * Enthir's dialogue after he gets the rubbing has a typo, he says 'undertsand' instead of 'understand'.
 * If the Dragonborn shouts in Calcelmo's Laboratory, with the door near the first valve open, the normal guard will come over to them and tell them not to shout, even if in sneak mode. After the dialogue he will catch the Dragonborn for trespassing.
 * The journal entry still reads "I'll have to find a way to make the information more portable" even after making the rubbing.
 * Aicantar has an alternate dialogue in the lab about hearing a noise (instead of a saboteur) if the player makes it past him without activating a trap in the previous room.
 * If sneaking and undetected, one can hear some conversations along the way to the Falmer Stone:

Wizard's Guard 1 "What do you think this is?" Wizard's Guard 2 "Another trap, most likely. Things are dangerous...three guards died when the lower hall flooded with steam last week."

And after getting the rubbing, if one set off the trap near Aicantar: Aicantar "Accidents like this just don't happen. Someone is trying to sabotage my uncle's research." Aquilius "I...all right. If there is a thief, he won't leave this tower alive. But shouldn't we inform Master Calcelmo?" Aicantar "I'll deal with my uncle. Just...go! Scour this place from top to bottom!"
 * The dead guards in the hall filled with poison gas are actually Markarth Guards, not Wizard's Guards.

Bugs
Risposte Complicate