Mortal Shell 2: How to Unlock the Alchemist’s Workshop (Full Walkthrough)

The Alchemist’s Workshop is a hidden dungeon tucked into the exterior mines that link Castigator’s Keep to the Lonesome Spire in Mortal Shell 2. Its entrance is sealed until you either blast it open with a siege weapon or break the illusory wall covering it, and the run ends with a serpent boss guarding the Clockwork Shardstone.

Quick answer: Grab the Makeshift Projectile from the southern cliff edge in the Outskirts of Mammon, load it into the catapult southeast of the Outskirts of Mammon beacon, and fire it. The shot punches open the cave entrance on the wooden platforms below Castigator’s Keep, which loads the “ALCHEMIST’S WORKSHOP” location banner when you walk in.

Two ways to open the Alchemist’s Workshop entrance

The dungeon door is a rock face on the cliffside path southwest of Castigator’s Keep. Both methods lead to the same opening, and neither locks the other out.

Method	What it takes
Catapult puzzle	Collect the Makeshift Projectile in the Outskirts of Mammon, load the catapult, and fire it at the distant cliff wall.
Illusory wall	Walk the wooden platforms below Castigator’s Keep and strike the false wall covering the entrance directly.

The catapult route is the intended one and is easier to spot on the map. If you have already wandered the mines and hit the wall, the entrance stays open and the projectile becomes optional.

Makeshift Projectile location and how to fire the catapult

Rest at the Outskirts of Mammon beacon and head through the ruins toward the ravine. Shooting the rope near the far side drops a wooden bridge and opens a shortcut you will reuse on the way back.

Cross the bridge and clear the Grisha warriors patrolling the cliff. A scribe’s note sits along this path, describing a payment owed to “Bartol” for building a “sealed wall” for someone called “Sariel” — a fairly direct hint at what you are about to break open.

Continue to the southern grassy cliff edge, past the NPC Vlas under the stone bridge, and pick up the Makeshift Projectile. It appears in your inventory as a single-use siege item.

The Makeshift Projectile pickup notification appearing on the cliff edge in the Outskirts of Mammon — The Makeshift Projectile is picked up on the southern cliff edge of the Outskirts of Mammon.

Return toward the beacon and run southeast to the large wooden catapult overlooking the canyon. Interact with it, confirm the “Place Ammo?” prompt to load the projectile, then fire.

The shot travels across the canyon and tears a hole in the distant rock face. That hole is the dungeon entrance, and it stays open permanently.

How to reach the dungeon from Castigator’s Keep

Fast travel from the Outskirts of Mammon beacon to Castigator’s Keep. The entrance sits in the mines below the keep, so approaching from above is much faster than walking the canyon floor.

Player running the path toward the large tree shrine after fast travelling — The route out of the beacon area runs past the large tree shrine before dropping toward the mines.

Ride the wooden lift down and follow the winding cliffside trail across the bridges. Miners patrol this stretch, and a ranged sidearm thins them out before they crowd the narrow planks.

Drop down past the mining camp onto the wooden platforms and head into the blasted rock opening. The “ALCHEMIST’S WORKSHOP” banner confirms you are in the right place, and another elevator carries you down into the dungeon proper.

Alchemist’s Workshop walkthrough: Library, illusory wall, and greenhouse

The opening chamber throws a Crescent Knight and a group of Miners at you, and Woodmen join partway through the fight. Pull them toward the entrance rather than fighting in the middle of the room.

Gloom pickup notification appearing as the armored shell fights through the dungeon cave — Gloom drops from the enemies in the first cave chamber of the workshop.

The next room holds a Viletongue. A side room on the left contains a Dorsalite, and the stairs beyond it lead past a Galvanic Shard. A small alcove before the study stocks a Common Moonshine.

The study is full of scrolls, anatomical wall drawings, and notes from the alchemists. One records the completion of the Stellarium and claims “the ovum appears to be responding,” which explains the starry cavern waiting at the bottom of the dungeon.

Go to the bookshelf at the end of the room and use the interactable book. The shelf slides aside and exposes a bare stone wall behind it.

Player standing in front of the tall bookshelf that hides the illusory wall — The bookshelf in the study hides the illusory wall that opens the rest of the dungeon.

Attack that wall. It is illusory and breaks apart, opening the archway into the greenhouse. Rolling into it does nothing, so you need an actual weapon swing.

Clear the greenhouse, which is stuffed with oversized fungus growths, cauldrons, and drifting spore clouds. A Bloodseed sits in the middle of the room.

Cell block, Sheephead Totem, and the Alchemical Elixir path

Push into the cell block and deal with the Arbiter of Flesh and the Brigand manning a ballista. Break the ballista’s line of sight using the pillars while you handle the melee threat.

Look above the middle of the three cells for a small button and shoot it. The cell opens, and killing the sheep inside yields the Sheephead Totem.

Find the table opposite the cells and drink the Alchemical Elixir. Your camera angle twists and you lose a trickle of health while the effect lasts, and a Mycellian Skulk rushes you during it. Standing still and waiting it out is the safest option once the enemy is dead.

A passage appears next to the table. Cross the narrow wooden bridge carefully — the distorted perspective makes the edges hard to read — and collect four Glimpses and the Synaptic Vessel from the altar bowls at the end.

Pull the lever beside the altar. The message “A gate has lifted” confirms the closed gate back in the cell block is now open.

The lifted gate and the elevator shaft leading down to the lower level of the workshop — Pulling the lever raises the gate and reveals the lift down to the final chamber.

Note: the elixir path is the only way through. There is no alternate route into the lever room, so if the passage has not appeared, you have not drunk the elixir yet.

Serpent boss fight and the Clockwork Shardstone

Backtrack through the raised gate and step onto the lift. It breaks partway down, dropping you into the lower tunnels where Curseblood Funghouls wait. Clear them before pushing into the open cavern.

The final chamber is the starry cavern lit like a night sky, and it holds a large serpent-like boss. Its grab attack is the dangerous one — being caught kills your shell outright, so keep moving laterally and punish after its lunges rather than trading hits head-on.

Once it is down, open the ornate stone chest at the back of the room for the Clockwork Shardstone, a Tarstone you can inspect and equip from the Tarstones menu. Before you leave, hit the glowing blue tree-like nodes around the chamber for extra Glimpse, then use the rift to return to the workshop entrance.

Alchemist’s Workshop full item list

Item	Where to find it
Dorsalite	Small side room left of the Viletongue chamber
Galvanic Shard	On the stairs leading down from that room
Common Moonshine	Alcove just before the study
Bloodseed	Center of the greenhouse room
Sheephead Totem	Middle cell, opened by shooting the button above it
Glimpse x4	Altar at the end of the elixir passage
Synaptic Vessel	Same altar, beside the Glimpses
Clockwork Shardstone	Chest behind the serpent boss in the starry cavern

The dungeon is rated medium in size and contains four lootable chests, 21 enemies, eight traps, five readable notes, and nine gates and hidden walls in total, so sweeping every corridor is worth the detour if you are chasing full clears.

Why the entrance or the secret room won’t open

The catapult gives no prompt. You do not have the Makeshift Projectile. It only spawns on the southern cliff edge in the Outskirts of Mammon, past Vlas under the stone bridge.
The wall behind the bookshelf won’t break. Interact with the book first so the shelf moves, then strike the exposed wall with a weapon attack.
No passage next to the table. The route only appears after you drink the Alchemical Elixir; the distorted camera is the effect working as intended.
The gate at the end of the cell block is still shut. The lever sits past the elixir bridge, next to the Glimpses. Look for the “A gate has lifted” message to confirm it triggered.

Everything in the workshop can be done in a single trip once the entrance is open, and the Clockwork Shardstone is the run’s payoff. If you would rather skip the siege puzzle entirely, walk the platforms below Castigator’s Keep and break the illusory wall — the dungeon and its loot are identical either way.