This private museum, owned and curated by Professor Brianna Ashworth, recently closed to the public. After a number of patrons disappeared, as well as those seeking their missing kin, public outrage lead to a hiatus for all upcoming exhibitions.

Purpose / Function

Initially the museum was a genuine place for the acquisition and storing of knowledge relating to the history of Ravnica. Brianna Ashworth focused on artefacts, and the architectural history of the great city. An expedition to the Undercity Mantle returned with an esoteric charm of carved bone, as well as a some lost texts. This building now stands as an edifice to hide the secret lair of a cult of witches, members of the Briarheart Sisterhood.

Denizens

Above

Mimics Hoard Mimic (dragon skeleton, which draws in the other displayed skeletons and display items into its form.) Animated armor 1 statue of Lady Briarheart behind a locked door upstairs

Below

Several statues of Lady Briarheart
Briarheart High Priestesses: Brianna Ashworth Trimble Lizzie
Briarheart Witch Neophytes
Gravehounds
Zombies & skeletons
The remains of Priest Byron Bay (semi sentient) The remains of Colonel Emmet Bregman

Valuables

Journals and a map (carved into leather of dubious origin) indicate a number of small coven settlements in the undercity of Precinct 3, concentrated under the Voda Vidi's Vernadi. The journals indicate a working relationship with an entity they refer to as the 'tear drinker', a mutually beneficial arrangement where the entity permits safe travel beneath a wellspring of green mana, while the witches presence tainting the nature above. This corruption appears to serve the entity's machinations. It has attempted to make pacts with members of the coven, to no success. The witches seem to be devoted to their sisterhood.
Oil painting of an ocean with a small city on the horizon. The longer the viewer observes the painting, the closer the city appears to be. They experience an effect similar to the spell Hypnotic Pattern, and must make a DC 16 Wisdom saving throw. On a failed save, the creature is charmed by the painting, is incapacitated with a speed of 0. They remain charmed until they either take damage, someone takes an action to shake the person out of their stupor, or the individual passes out. They ignores hunger and thirst, and is compelled to make a DC 15 Constitution save after 24 hours of being charmed by the painting. Individuals forced out the charm are immune for 24 hours, those who lost consciousness instead make their save at disadvantage. 
Some of the displays contain petrified wood fragments that look the same as pieces of bone charms, with esoteric symbols carved into their faces. 
Archaeological data regarding the 2 dragon corpses discovered beyond the Undercity Mantle at separate locations. The first is hypothesised to have died in combat, with a number of fractures and punctures in its skeleton. This is the skeleton on display in the museum, and is the centre of the Hoard Mimic. The second is only described, but does not appear to be at the museum. Analysis of the skeleton have difficulty determining the cause of death. The bones appear to have holes bored into them, but don't appear to be the cause as the bone density around these holes show signs of healing. Brianna hypothesises that foreign objects may have occupied these holes. Furthermore, the bones show signs of cancerous growth throughout. This second skeleton was found with a number of charms, many made on petrified wood, and a single made on bone (this being the one that Breanna fixated on)
Books on ancient Ravnican life. Book describing a period where cemeteries and altar tombs were banned. Cremation became standard practice, but there was resistance due to cultural traditions associated with the internment of the dead. References the folk legend of the Undertaker, who loved his work but found his dream turn dark. He began to believe the cemetery had a mind of its own. The cemetery was on the outskirts of town, and after some time even the towns folk heard a hideous series of noises and could see something enormous lumbering above the treeline that drew them to see. But when they arrived, the cemetery was gone, now only an irregular shaped hole in the ground, all the surrounding flora desiccated and twisted.      Other stories warn against dwelling to much on memories of the dead when visiting graveyards. An old elven poem reads; "Lay not your flowers at the stone When walking this cold place alone Make haste in this garden of dead Lest you hear its voice within your head"

Alterations

After Ashworth's decent in occultism, the area beneath the museum was reclaimed and repurposed into a private place the witches could develop their connection to Lady Briarheart, and the Sleeping City she venerated.  Their explorations into profane artifice resulted in the creation of a number of mimics. While it is possible that these murderous imitators escaped the caverns below, it is just as likely the witches placed them in the museum for their own perverse amusement. The caverns below descend like an inverse wizard tower, with the architecture becoming more and more corrupt. Corpses fuse with stone as undead creatures denied release while the halls and stairways are stalked by gravehounds.  At the very lowest level holds the coven's communal ritual space, a large open space surrounded by a series of interconnected spaces. This area is where the grotesque combination of undeath and artifice is the most intense.

Ashworth Museum, ground floor

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Mimic Museum

The The Ashworth Museum of Natural and Supernatural History has stood as a cultural and intellectual cornerstone for decades, featuring artifacts both manmade and otherwise. Lately, however, its halls have been empty, its coffers emptier, and its director—a stern and eccentric woman Brianna Ashworth—has withdrawn from public life. The cause is at once obvious and yet baffling: guests and employees have begun to go missing. With some (though few) of their remains turn up some days later in the sewer system, bloated, shredded, and bloodied. Things have gotten so dire, in fact, that the people of the neighbourhood have begun rumbling about burning the museum to the ground.

General Features

The following features are common throughout all areas of the museum and are printed here for ease of reference:
Size & Dimensions. Treat the ceilings within each area of the museum as being 15 feet high unless stated otherwise. If you are using the maps provided, treat each square as being five feet.
Illumination. If the party is investigating during the day, treat each area as being well lit by natural sunlight. If the party is investigating during the night, treat each area as being dimly lit by moonlight.
Surface Detail. The museum is constructed of treated oak wood and marble stone. Large windows of glass are inset into the walls and ceilings, providing plenty of light. Locks. Several doors and display cases throughout the museum are locked. Characters can make a DC 14 Dexterity check using thieves’ tools to unlock them or break them open with a DC 16 Strength (Athletics) check.
Creature Mimics. In several exhibits, mimics are imitating different creatures. These creature mimics use their own statistics, except with the following changes:

• The mimic is a monstrosity and gains the shapechanger tag.
• It gains immunity to acid damage and the prone condition, but loses all other resistances or immunities.
• The mimic has darkvision out to 60 ft.
• New Trait: Shapechanger. The mimic can use its action to polymorph into an object or back into its true, amorphous form. Its statistics are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.
• New Trait: False Appearance (Object Form Only). While the mimic remains motionless, it is indistinguishable from an ordinary object.
• If the creature has the Immutable Form trait, it loses it.

Don’t Drop That!

Special care must be taken during the adventure to prevent unnecessary damage to the museum’s artifacts and structure. Whenever any creature misses an attack, casts a spell that damages an area or forces a saving throw, or directly targets a museum piece, the GM must roll a d6 and multiply the result by the level of the adventure (3). When it comes time for the characters to collect their reward, subtract these results from the total gold value (including items). See "Concluding the Adventure" for more information. Additionally, if an area in which a battle takes place contains treasure as noted in its section, roll a d20 in addition to a d6. On a 1-5, the treasure is destroyed (it may still be collected and possibly repaired, however).

Concluding the Adventure: What’s the Damage?

Once all the mimics and armor have been cleared from the Museum, the patron will spend the next few hours surveying the damage. They will, hopefully, be horrified at the carnage wrought upon their precious investment— horrified, but thankful for the characters’ help anyway. To calculate the party’s final reward (1500 gp), subtract all damage incurred throughout the museum from whatever was promised initially (include the value of items promised, if any). However, if any of the objects were stolen by the characters, and no attempt was made to cover their tracks, the patron will demand their immediate return or threaten to contact the authorities.

Ashworth Museum, top floor

Open full size

Mimic Museum

The The Ashworth Museum of Natural and Supernatural History has stood as a cultural and intellectual cornerstone for decades, featuring artifacts both manmade and otherwise. Lately, however, its halls have been empty, its coffers emptier, and its director—a stern and eccentric woman Brianna Ashworth—has withdrawn from public life. The cause is at once obvious and yet baffling: guests and employees have begun to go missing. With some (though few) of their remains turn up some days later in the sewer system, bloated, shredded, and bloodied. Things have gotten so dire, in fact, that the people of the neighbourhood have begun rumbling about burning the museum to the ground.

General Features

The following features are common throughout all areas of the museum and are printed here for ease of reference: Size & Dimensions. Treat the ceilings within each area of the museum as being 15 feet high unless stated otherwise. If you are using the maps provided, treat each square as being five feet. Illumination. If the party is investigating during the day, treat each area as being well lit by natural sunlight. If the party is investigating during the night, treat each area as being dimly lit by moonlight. Surface Detail. The museum is constructed of treated oak wood and marble stone. Large windows of glass are inset into the walls and ceilings, providing plenty of light. Locks. Several doors and display cases throughout the museum are locked. Characters can make a DC 14 Dexterity check using thieves’ tools to unlock them or break them open with a DC 16 Strength (Athletics) check. Creature Mimics. In several exhibits, mimics are imitating different creatures. These creature mimics use their own statistics, except with the following changes:

• The mimic is a monstrosity and gains the shapechanger tag.
• It gains immunity to acid damage and the prone condition, but loses all other resistances or immunities.
• The mimic has darkvision out to 60 ft.
• New Trait: Shapechanger. The mimic can use its action to polymorph into an object or back into its true, amorphous form. Its statistics are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.
• New Trait: False Appearance (Object Form Only). While the mimic remains motionless, it is indistinguishable from an ordinary object.
• If the creature has the Immutable Form trait, it loses it.

Don’t Drop That!

Special care must be taken during the adventure to prevent unnecessary damage to the museum’s artifacts and structure. Whenever any creature misses an attack, casts a spell that damages an area or forces a saving throw, or directly targets a museum piece, the GM must roll a d6 and multiply the result by the level of the adventure (3). When it comes time for the characters to collect their reward, subtract these results from the total gold value (including items). See "Concluding the Adventure" for more information. Additionally, if an area in which a battle takes place contains treasure as noted in its section, roll a d20 in addition to a d6. On a 1-5, the treasure is destroyed (it may still be collected and possibly repaired, however).

Concluding the Adventure: What’s the Damage?

Once all the mimics and armor have been cleared from the Museum, the patron will spend the next few hours surveying the damage. They will, hopefully, be horrified at the carnage wrought upon their precious investment— horrified, but thankful for the characters’ help anyway. To calculate the party’s final reward (1500 gp), subtract all damage incurred throughout the museum from whatever was promised initially (include the value of items promised, if any). However, if any of the objects were stolen by the characters, and no attempt was made to cover their tracks, the patron will demand their immediate return or threaten to contact the authorities.