I'm stuck

[turkish ambassador]

Okay, so I did the following things:
Explored Forgotten Rods, Fungal Wastes, Crystal Peak, Resting Grounds, Royal Waterways, Ancient Basin(can't get to the Abyss), City of Tears, Deepnest, Howling Cliffs. I reached Crystal Peak and got the Pale Ore from there.
I have Isma's Tear, Monarch Wings, Mothing Cloak, Vengeful Spirit(+ its upgrade), Crystal Heart, Mantis Claw and Desolate Dive. On top of that, two nail arts from Greenpath and Howling Cliffs.

I defeated most, if not all bosses in these areas including 1 dreamer at the top of City of Tears.

I have gathered 3 pale ores and got second to last nail upgrade.

I've got myself a train pass and I think I only have 1 stag left to find(in Queen's Gardens)

I have 8 masks of health, decent amount of charms(~30) and 8 notches.

Now I just hit a dead end and I have no idea where to go and what to do.
What comes next? Where am I supposed to go to continue the plot? I tried to access Queen's Gardens but there seems to be black/shadow gate that I can't pass through and the entrance from Greenpath is closed and needs to be opened from the other side. I can't get to the Abyss from Ancient Basin either.

While we're here, if I complete the plot will I be able to backtrack and get 107% completion?
Also, how and where do I start the Grimm Troup DLC? Will I be able to play it after completing the main story?

Sorry for a long post but I am just overwhelmed by the vastness of this game. I completed The Witcher 3 fully and it feels like nothing compared to Hollow Knight.

[Ellixer]

I'd worry about completion percentage after you get all the endings.

You need to go to Kingdom's Edge, through either Royal Waterways or the City of Tears. After you get a certain item, you can head to the Abyss. There you can unlock an item that opens up exploration (and give you access to a Dreamer).

You also need to kill the Dreamer in Deepnest.

The Grimm's Troupe can be started after you complete the main story. It does however, include a bunch of fetch quest that is better done as you go along, as they can be a chore to do all at once, so starting them now is probably better (though the final boss of that DLC I would recommend doing after you beat the main story). In Howling Cliff, a corpse of a large bug is hidden behind a wall. Hit it with your Dream Nail, and then go hit the pyre to the left of the bug repeatedly. Then return to Dirtmouth and proceed from there.

Ask again if you've done all this and get stuck again. Remember that there are three endings available, and unlocking two of them require some extra work.

[Ellixer]

Forgot to add. Yes you can go back to the game after finishing the story. Loading the save will simply put you outside the boss room, with the boss added to the journal. You will never be put in a situation where you cannot reach 107%, though one of the three endings can be permanently locked off (though that's not a big deal, since it's very similar to another ending that will become available).

[The Last Hunter]

you need to go to kingdoms edge and fight hornet to get to the abyss them you can get the sade cloak to go past that shadow gate then get the other dreamers the one in city of tears is the hardest in my opinion due to watcher knights one of the dreamers is in fog canyon ismas tear is needed for this part you can get to fog canyon from queens station (not gardens)
the other is in deepnest you need to beat the mantis lords in fungal wastes to go there

[turkish ambassador]

Is it possible to get all 3 endings in one playthrough? Or do I have to finish the game 3 times in order to get all 3 achievements?

[The Last Hunter]

Originally posted by `JZ:

Is it possible to get all 3 endings in one playthrough? Or do I have to finish the game 3 times in order to get all 3 achievements?

the game sends you back before you beat the last boss so yes you can get multiple endings in 1 playthrough (forgot to add one ending can be locked off so beat the last boss once before doing the extra stuff to get the other 2 endings)

[Kanra]

For convenience, you could head to Kingdom's Edge as it does open a few doors in terms of progress. To do that, you either need to head to the very right in the City of Tears or simply take the tram right from Ancient Basin. First way gets you a map easily, second way gets you next to a sub area quicker.

You also have the option of going for the other Dreamers. The one in Deepnest can be reached normally (or via stag for convenience if you have it), while the one in Fog Canyon can be reached by crossing the acid pools in the bottom left of the Crossroads or across from Leg Eater in Fungal Wastes.

Queen's Gardens can be entered by heading up and left immediately from the Queen's Station entrance of Fog Canyon. All you'll have to do from there is continue left and past the acid pool.

As far as completion goes, you can go for it at any point in the game as you can't lock yourself out of that nor the Journal. Every alternative to something provides the same amount of completion so mutually exclusive aspects don't lock you out.

For the Grimm Troupe, head to the Howling Cliffs and look for a breakable wall below the entrance that leads to the Joni's Blessing area. You're looking for a red bug corpse to dream nail (it's all the way to the right after you break some walls). Once that's done, simply hit the object in the previous room with your nail a few times. After that, head to Dirtmouth.

Originally posted by `JZ:

Is it possible to get all 3 endings in one playthrough? Or do I have to finish the game 3 times in order to get all 3 achievements?

Yes, you can get all 3 endings in one playthrough. After finishing the game, you are able to load your savefile which will place you at the last bench you sat at. To get all 3 endings in one run, you'll have to finish the game once before getting a certain charm (it requires a lot of work, so it's nothing you can just do by accident) to get the missable ending.

Originally posted by Ellixer:

After you get a certain item, you can head to the Abyss. There you can unlock an item that opens up exploration (and give you access to a Dreamer).

He already has access to that Dreamer regardless.

[Krpa]

If you want the achievement, make sure to beat the last boss with 100% or more.