Control Resonant: How to Follow the Relays to Grist in the Underpass

Late in Recursions and Iterations, Dylan’s search for the missing research team turns into a traversal puzzle. After the Cross the Chasm objective, the Underpass stops giving you a single waypoint and instead strings a line of flashing red beacons across a collapsed stretch of concrete. Those beacons are the path to Grist, and the route only reads clearly once you know which ledges are load-bearing and which are scenery.

Quick answer: Activate the relay machine on the platform after crossing the chasm, then move from red beacon to red beacon — ledges, pillars, green-foamed pipes, the desk platforms — until Dylan calls out to Grist at the lit workstation.

What you need before the relay route unlocks

This objective sits deep inside a mission that is gated by Jesse’s Fault chain. If the Underpass looks impassable long before the chasm, the blocker is almost always a traversal ability you have not picked up yet rather than a hidden door.

Shift, unlocked by completing The Incursion Fault in the West Incursion Zone.
Reach, unlocked by completing The Subway Fault in the Evacuation Zone.
The Underpass Fault, approached from The Spire once you have Reach.
The earlier Recursions and Iterations beats: restoring the power, locating Grist, and defending the transmission tower.
The time fluctuation at the cable car, which feeds directly into Cross the Chasm.

Recursions and Iterations is the mission where Control Resonant stops running one quest at a time. If your log still shows an unfinished Fault, finish it first — the chasm route expects both traversal abilities.

The full route to Grist, beacon by beacon

On the far side of the chasm, walk up to the machine standing alone on the platform and interact with it. The Quest Updated prompt fires immediately and the objective changes to Follow the Relays to Grist.

Activating Initial Relay — The first relay machine on the platform past the chasm, with the activation prompt showing. Shown at 00:06 in Trophy Tom’s video. Image: Remedy Entertainment

Turn to the stacked concrete blocks beside the orange pipes and climb. There is a Power Upgrade Point 3/3 sitting on the ledge here, so grab it before you pull yourself up onto Underpass 3.

Follow the narrow concrete ledges that run above the orange-lit chasm. The first flashing red beacon marks the correct side, and every time you lose the line, look for the next red light rather than the nearest gap.

Following Red Beacons Above the Chasm — The narrow ledge run toward the first red relay beacon above the chasm. Shown at 00:20 in Trophy Tom’s video. Image: Remedy Entertainment

The ledges end in a stretch of free-standing concrete pillars and blocks hanging over glowing orange mist. Jump between them one at a time, keeping the beacon line ahead of you as your heading.

Platforming Across Chasm Pillars — Platforming across the suspended concrete pillars above the orange mist. Shown at 00:43 in Trophy Tom’s video. Image: Remedy Entertainment

Land near the large rusty pipes coated in greenish foam. The pipes themselves are the walkway — track along them until you pass the next red light beacon.

Push into the tight corridor smothered in white foamy growth. Dylan finds a body on the floor labelled Dylan’s Corpse here and reacts to it out loud. Nothing needs to be fought or interacted with; keep moving through.

Cross the open cavern that sits above thick white and yellow mist, aiming for the block of concrete structures on the far side.

Scale the concrete wall into the open-sided room full of office desks and typewriters, then vault the gaps and climb to the higher desk platform set against a red wall. Dialogue about crossing the chasm plays across this stretch, which is a good sign you are still on the intended path.

Drop down from the upper desks into the alcove holding a lit workstation with a chalkboard sketch of an arrow going into a box. Head for the doorway beyond it and Dylan calls out to Grist.

Landmarks in order, if you have lost the beacon line

The route never doubles back on itself. Use these markers to check whether you are ahead of or behind where you think you are.

Order	Landmark	Note
1	Relay machine on the platform	Triggers the objective
2	Orange pipes and block climb	Power Upgrade Point 3/3
3	Underpass 3 ledges	First red beacon
4	Chasm pillars	Jumps over orange mist
5	Green-foamed pipes	Second red beacon
6	White growth corridor	Dylan’s Corpse
7	Misty cavern	Head for the concrete blocks
8	Desk and typewriter rooms	Climb to the red wall
9	Lit workstation alcove	Chalkboard drawing, doorway to Grist

How to confirm the objective is complete

There is no boss or arena at the end of this stretch. The confirmation is the quest tracker itself: once Dylan reaches the workstation alcove and moves through the doorway calling for Grist, the Recursions and Iterations objective rolls over to Place the final probe relay. If the tracker still reads Follow the Relays to Grist, you have stopped short of the doorway past the chalkboard.

Why the final probe relay matters

The relay placement that closes out Recursions and Iterations is the last piece of the probe array the FBC has been building since the descent under the Evacuation Zone. That work began with Into the Sinkhole, where Dylan escorted the relays down by diving bell.

Map Location — The Into the Sinkhole marker in Evacuation Zone 3, where the probe relay work started. Shown at 00:04 in PowerPyx’s video. Image: Remedy Entertainment

At Bedrock, the relays are pulled one at a time from a central unit and carried out to marked terminals across floating platforms and elevated ledges. Four of them complete that array, after which the area turns hostile and the diving bell cable snaps.

Installing the First Probe Relay — Picking up a Probe Relay from the central unit at Bedrock before carrying it to a marked terminal. Shown at 02:39 in PowerPyx’s video. Image: Remedy Entertainment

Knowing that pattern is useful when the Underpass asks for the last one, because the interaction is the same kind of carry-and-activate job rather than a new system.

Installing the Fourth Probe Relay — Activating the fourth relay on a high platform, completing the Bedrock array. Shown at 04:11 in PowerPyx’s video. Image: Remedy Entertainment

With Grist found and the relay chain finished, Recursions and Iterations wraps up and the campaign turns back toward the Oldest House for The House in Distress. Before you go, the Underpass is worth another pass for upgrade points — the next Resonant Cycle brings everything you have killed back a little stronger.