Recursions and Iterations in Control Resonant (Full Walkthrough)

Recursions and Iterations is the main story mission that sends Dylan Faden under the Sinkhole to find a missing FBC research team led by Dr. Grist. It is also the mission where most players get stuck, because the route dead-ends at a gap you physically cannot jump. The fix is another quest entirely, and the rest of the Underpass only makes sense once you understand that the research camp exists three times over.

Quick answer: The Underpass chasm stays impassable until The Subway Fault grants you Reach. After that, work the three research sites, restore the power, ride the cable car, and place the final probe relay.

Why the quest stalls at the Underpass chasm

After Emily Pope sends you below the Sinkhole, the objective reads “Locate the Research Team” and the path through Underpass 1, 2 and 3 works normally. Then you reach a ledge overlooking a distorted void with the objective marker clearly on the far side. No amount of double-jumping or dodging closes that gap. It is a deliberate navigational softblock, not a missed platform.

Zoe flags a report about the Subway Fault at roughly the same moment, and that is the hint. Jesse Faden’s Faults are part of the traversal progression, so the ability you need to keep going is locked behind one of them. Unlock the Halfway Trail fast travel door on that ledge before you leave, because you will be coming straight back to it.

A vision of Jesse also appears in the Underpass near an island of orange pipes, which starts The Underpass Fault. That one cannot be entered until the Evacuation Zone Fault is done first, so treat the subway as the priority.

Route from the Oldest House lobby down to the Underpass

Speak to Emily Pope in the Oldest House lobby to start the mission. The objective updates to “Find the Team Below the Sinkhole” and the Thomas Street Exit opens your way back out into Downtown.

Cross Downtown over the rooftops and water towers until you reach a fast travel door, then warp to Evacuation Zone: Main Street. Skipping the street-level route saves several minutes of Hiss encounters.

Downtown Map — The map with Downtown 2 and Central 6 marked, used to line up the fast travel jump. Shown at 01:21 in Trophy Tom’s video. Image: Remedy Entertainment

From Evacuation Zone 5, climb the rooftops, drop down the fire escapes and enter the Laundromat security checkpoint. Follow the green-lit stairwells beneath it into the shifted apartment corridor.

Ability Barrier Map Check — Evacuation Zone 5 on the map, with the Ability Barrier tooltip that marks blocked routes. Shown at 02:37 in Trophy Tom’s video. Image: Remedy Entertainment

At the ledge marked “CHASM AHEAD”, hop the floating rooms to the hanging metal platform and activate its power console. Riding it down drops you into the vertical container shafts of the Sinkhole proper.

Take the spiral stairs down into the expansion tunnels. Grab Power Upgrade Point 2/3 on the way past, then keep descending until the location title “UNDERPASS” appears over the floating geometric pillars.

Navigating shifting paths — The Underpass corridors shift around you as you move between sections. Shown at 00:22 in Trophy Guides’s video. Image: Remedy Entertainment

Four fast travel doors open across this stretch, and all of them save real time later:

The Spire — the deserted camp with the research equipment in Underpass 2.
Halfway Trail — the ledge at Underpass 3, right before the impassable gap.
Patterned Metro Tunnels — your exit from the subway in Evacuation Zone 6.
Research Stations — unlocked at the second research site once you are across the chasm.

The Subway Fault: How to unlock Reach

Fast travel back to Evacuation Zone: Main Street. The Board speaks on the rooftop and the quest The Subway Fault appears, pointing you at the subway entrance down at street level. The station stairs are marked by a blue-green distortion.

Head down into the tiled concourse and onto the live tracks. Ghostly trains run the tunnels on a loop, so duck into the wall alcoves whenever one is bearing down on you.

Push through the mold-covered section past the Spore Mothers and Mold Blights. Nothing here has to be killed if you keep moving toward the broken tunnel floor.

Platform down the vertical chasm of suspended subway cars, catching the lower track sections as you fall. Climb back out and take the orange sloping tunnel up into the Fault.

Cross the golden meadow to the floating platform, talk to Jesse Faden and help her complete the ritual. That awards Reach, which grapples you to glowing Gravity Anomalies and flips your personal gravity onto that surface. Reaching a normal surface returns you to default gravity, and the ability has a limited range, so close the distance with a double-jump and dodge first.

The Subway Fault Completed — The Subway Fault closes out once the ritual is done and Reach is yours. Shown at 19:41 in Trophy Tom’s video. Image: Remedy Entertainment

Use Reach to climb back up through the subway ruins to Evacuation Zone 6 and activate the Patterned Metro Tunnels door. Warp to Halfway Trail, return to the gap, and grapple the Gravity Anomaly to cross.

Inverting perspective — Reach flips your orientation onto walls and ceilings, which is how the Underpass gap gets crossed. Shown at 00:28 in Trophy Guides’s video. Image: Remedy Entertainment

The three research sites and how to tell them apart

Past the chasm, the mission stops being a traversal problem and becomes a timeline problem. The same research camp exists three times across the floating pillars, each one showing a different version of what happened to the team. They look nearly identical, so use their fixed landmarks rather than the layout to work out where you are.

Site	Landmark	What happens there
Site 1	Cable car station and generator consoles	Team found dead, later Ayad alive, power puzzle, chasm crossing
Site 2	Research Stations fast travel door	Schultz’s team disintegrates, Grist Research Log #3, route to the tower
Site 3	Far camp past the pillars	Grist alive, her tracking device on the table, the ledge jump

On the first pass, visit the sites in sequence. At Site 1, report the dead researchers; at Site 2, report the anomaly after Schultz and the others fall into corpses before you; then reach Site 3, where the team is alive and Dr. Grist is available to speak with. Before leaving, take Grist’s Tracking Device from the folding table. That acquisition changes the objective to “Track the Time Fluctuations”.

How to restore the power at the first research site

Return to Site 1 with the tracking device and speak to Ayad beside the console. He explains that the facility has lost power, then indicates the tape on the floor. Leave the tape alone at first and inspect the yellow wires running from the console; they guide you to the main generator room, which contains four power cores, three of them inactive.

Follow one strip of yellow tape away from the generator room. Each strip ends at a small auxiliary room containing a single active power core, including Unit 1 and the upper generator chamber above it.

Grab the charge and immediately retrace the same route back. The charge only stays live for a short time, so do not detour or explore on the return leg.

Deposit the charge into a dead core in the main generator room, not any other room that looks similar. Repeat for the remaining two cores.

Use Reach on the anomalies along the way to cut the return trip short. Reorienting gravity turns walls into direct paths back to the generator room and is often the difference between making the timer and losing the charge.

Completing the circuit makes all the cabling glow yellow, confirming that the puzzle is finished. Go back to Ayad, who is collapsed and dying beside his own corpse—a grim sight, but the intended result.

Locate Grist, then defend the transmission tower

Travel to Site 3. Schultz tells you Grist went out to set up probes, so follow the red lights out to the open precipice. Speak to her there and she jumps into the chasm.

Head to Site 2 and play Grist Research Log #3 beside the bodies. The objective changes to locating the transmission tower.

Climb the high platforms to the antenna tower and hold the area while the data uploads. Hiss forces spawn throughout, and the objective only clears when Zoe confirms everything has been transmitted to Pope’s team.

Cross the chasm and place the final probe relay

Return to Site 1 and the yellow cable car. This time Dr. Grist is alive inside it. Activate the console to ride across the chasm together.

Heading toward cable car — The platform route back to the cable car station at the first research site. Shown at 00:31 in Trophy Guides’s video. Image: Remedy Entertainment

On the far side, pick up the probe relay and carry it along the huge conduits and floating rock pillars. Power Upgrade Point 3/3 sits on this stretch, so sweep the platforms before you commit to the narrow pipe tunnels.

Climb the final vertical opening to the mound with the white tree, drop the relay into its mount, and trigger it.

The tree bursting into white blossom is the confirmation. Pope and Zoe come over the radio to confirm the data is coming through from beneath the Oldest House, the “Quest Completed” banner reads RECURSIONS AND ITERATIONS, and you receive the Prime Candidate Restraint Suit outfit along with a Living Shard. If the tree has not bloomed, the relay is not seated in its mount yet — interact again until the activate prompt fires.

From here the Underpass still holds separate business, including Jesse’s Fault and the region’s Resonant near The Spire, so check the quest name in the corner before chasing the nearest marker.