You cannot get past the main gate without getting the quest Along the Cold Trail.
The entrance to this dungeon crumbles and you will not be able to go pass the first room after completing The Varnhold Vanishing.
You need at least 2 characters (1 companion along with main character) to complete this puzzle.
Walkthrough[]
Numbered shapes are toggle plates.
Rectangles are shifting walls.
Walls shift open when toggling appropriate plate.
Match toggle plates and shifting walls according to color scheme.
Bell-shaped toggle plates have countdown timers. Running out of time results in walls closing back in.
Purple wall opens with successful perception check.
Open yellow walls.
Follow white line towards 2nd plate. Toggle 2nd plate.
Follow white line crossing orange wall. Clear area of monsters and disarm traps.
Leave behind one character for toggling 1st plate while everyone else stays in center room. Open green walls.
Follow white line towards 3rd plate. Toggle 3rd plate. The character that was left behind now have a path to rejoin the party.
Follow white line towards 5th plate. Clear area of monsters and disarm traps.
Leave behind one party member for toggling 5th plate while everyone else moves towards red wall. Open red wall.
Toggle 6th plate.
Follow white line towards spectres. Eliminate spectres.
Follow white line towards 4th plate. Eliminate soul eaters.
Leave behind two party members for 4th and 5th plates while one character moves towards three-colored wall. If you are short of party members, increase movement speed of the one you leave behind and make him run from 4th to 5th plate (or vice versa) to press them both quickly.
Cross the final wall and toggle master plate. It will open all colored walls permanently.