Control Resonant: Carbon Copy Quest Walkthrough (Parts I

In The Park, Carbon Copy unfolds across three side-story installments, with Dylan Faden trying to bring Heidi back together with her twin, Hannah, as Mold overtakes the district. A favor sets things in motion, a rooftop pursuit comes next, and the finale pits you against a boss in a factory overrun by Mold. Parts I and III are played on foot; Part II appears in your Quest Log automatically.

Quick answer: Get the apartment key from Heidi in The Park, tell Hannah that help is coming, then return to claim the Untapped Mother’s Locket. In Part III, go to the Park Factory and defeat Mold Hannah.

Requirements before you start Carbon Copy

You must have started the New Growth side quest first.
Carbon Copy begins in The Park, near the FBC Base and the map marker labeled “New Mold strains?”
The Budding Mycologist trophy needs both New Growth and the full Carbon Copy chain finished.

Carbon Copy Part I: Find Heidi’s twin sister

Heidi stands inside a raised, lit shelter near the middle of The Park, ringed by blue crystalline Mold. You can only reach it from above, so climb onto a taller rooftop and glide across the Mold growth into the shelter.

Land in the shelter and talk to Heidi, the girl in the pink jacket. She refuses to evacuate until she knows Hannah is alive and points you toward the apartment the sisters shared to the south.

Taking the quest gives you Heidi’s Old Apartment Key. Carbon Copy appears in Side Stories, and your objective switches to “Find Heidi’s Twin Sister in the Park.”

Set the apartment marker to the south as your tracked waypoint. Cross the Mold-covered rooftops, hopping between buildings on the Mold formations while following the yellow marker.

Deal with the rooftop threats before going inside. Flying Mold organisms with a glow patrol above and shoot projectiles; destroy every one to access the stairwell door. They leave Fungal Growth and Source behind.

Use the key on the rooftop access door, then go down the stairwell into the apartment hallway.

Go inside and collect the Letter To Hannah from the small table in the front living room. Then head along the hall to the bedroom.

Speak with Hannah in the bedroom. Tell her Heidi sent you and that an FBC evacuation team can help. She says she is safe, and the objective updates to “Return to Heidi.”

Go over the rooftops to Heidi’s shelter once more and speak with her. Confirm Hannah survived to finish Part I and earn the Untapped Mother’s Locket.

You know Part I is done when the side story leaves your Quest Log and the locket appears in your inventory. If the log still reads “Return to Heidi,” you have not finished that final conversation.

Carbon Copy Part II: Search for clues at the Field Hospital

Exploration won’t start Part II. After Part I is complete, returning to the Oldest House once you’ve finished “The Enemy of My Enemy” adds Part II to your Quest Log automatically. Zoe also contacts Dylan by radio, and the new stage may take a little time to appear.

Head to the FBC Field Office in Central and speak with Dr. Florez outside.

Go around the corner from Dr. Florez into the medical unit and talk to Hannah there.

Collect the file from the bed at the back of the room, along with the Note from Heidi, which raises doubts about who Hannah really is.

Return to Heidi and Hannah’s apartment. You will find Heidi’s body in the bathroom, which closes out Part II and opens the final part right away.

Carbon Copy Part III: Defeat Mold Hannah at the Park Factory

Part III begins immediately after Part II, back in The Park with the objective “Follow the Trail of Hannahs in the Park.” Frozen duplicates of Heidi and Hannah now stand along a path leading deeper into the district.

Start the quest from the rooftop above Heidi and Hannah’s apartment, then follow the row of unmoving clones.

Follow the route over the rooftops and descend across the huge blue-white Mold hills toward street level as Zoe guides you over the radio.

Head along the city road past parked cars and storefronts, then pass through the open parking garage lit in yellow to come out in the rear alley.

Come out of the garage and take the street toward the warehouse, going by the still Hannah clones. Heidi is waiting beside a locked roller door outside the Park Factory.

Speak with Heidi; she’ll give you the Park Factory Key and set the objective to “Try to Save Hannah.” Unlock the rolling shutter door with the key, then enter the factory infested with Mold.

Walk up to the enormous, mutated Mold Hannah and speak to her. She becomes hostile, your objective switches to “Defeat Hannah,” and the battle takes place along the raised walkway. Defeating her ends the fight.

Head back outside to the alley and finish talking to Heidi beside the semi-truck and shipping container to complete Carbon Copy: Part III.

The Mold Hannah fight drops +1 Thriving Spore, +246 Source, and the Mold Plague – Apex mod. Dialogue choices during these talks do not change any of the rewards.

All Carbon Copy rewards

Reward	Part	Source
Heidi’s Old Apartment Key	I	Given by Heidi on accepting the quest
Letter To Hannah	I	Living room table in the apartment
Untapped Mother’s Locket	I	Reporting back to Heidi
Park Factory Key	III	Given by Heidi at the factory door
Thriving Spore, Source, Mold Plague – Apex	III	Dropped by Mold Hannah
Untapped Medical Alert Bands	III	Final talk with Heidi
Budding Mycologist (trophy)	III	Completing the quest

How to confirm the quest is complete

The sequence is complete when the banner announcing the completion of Carbon Copy Part III disappears and Untapped Medical Alert Bands are added to your inventory. At that point, the Budding Mycologist trophy unlocks, and The Park’s zone meter gains 250 points, advancing from 425/1000 to 675/1000. These changes mean all parts of Carbon Copy are finished.