Determining what plane you are on

Question

In the game I'm in, we were all put onto some world, "some where".
The world we are on seems to be normal (normal gravity, etc), however there are zero gods.

Is there any way to determine what plane we are currently on?

Constraints:

We cannot use planar travel to leave (complicated, but it seems to involve death).
For game specific reasons, legend lore and similar spells that contact other deities/off world beings are not an option either.
DM won't give us the answer with a knowledge check, or through an NPC.

It's up to us players to figure it out.

To determine what plane you are on, reach into the seat back pouch in front of you and read the emergency card. They always list what plane it is for. :) Edited for format/organization — KorvinStarmast, Sep 25 '17 at 16:40
Unfortunately no. DM won't give us the answer with a knowledge check or through an NPC. Its up to us players to figure it out. — deadman1204, Sep 25 '17 at 16:46
I am voting to close this question as unclear: unless you can nail down exactly what the DM is and is not allowing, the only thing we can do is play a guessing game, trying to find things he’ll allow. That’s not how things work here; questions seeking ideas to try until something sticks is basically the epitome of questions we don’t do here. — KRyan, Sep 25 '17 at 16:56
What do you want me to say? I'm hoping there is a spell or something that can give more information about the plane you are on. For me it is a guessing game. Thats why I posted, I'm looking for ideas. — deadman1204, Sep 25 '17 at 17:00
@deadman1204 Suppose we suggest a spell. You ask your DM about it. He says that doesn’t work either. You edit the question, and that answer is deleted. Someone else suggests a feat. You ask your DM about that. He says that’s no good either, so you edit the question again, and that answer is deleted too. And that keeps happening until your DM okays something. That kind of back-and-forth is something the Q&A format cannot help you with. I’m sorry—frankly, were it my DM, I would object to playing the guessing game to begin with—but I really don’t think we can help you. — KRyan, Sep 25 '17 at 17:06
yup, extradimensional spaces work. The only limit is the players cannot use any sort of planeshifting. We can be ethereal or astral, but we cannot leave this world. — deadman1204, Sep 25 '17 at 18:28
You're on the xy-plane. (Unless you're a computer programmer -- then you're on the xz-plane.) — Mark, Sep 25 '17 at 21:56
Well usually the pilot makes an announcement like "this is flight 324 to Orlando. If you were bound for Mechanus instead, this is not your flight." — mxyzplk, Sep 26 '17 at 02:31

Hey I Can Chan · Answer 1 · 2017-09-26T13:43:27.770

The DM probably doesn't want you to know yet…

It sounds as if the DM would like the party's current plane be a mystery that's solved over the course of the party's adventures there. If this is the case—and, given the constraints the party's working under, it certainly sounds like it is—, it won't matter the steps the party takes to determine the plane the party's on because the party can't learn that information until the time is ripe. In short, DM fiat prevents—and will continue preventing—the party from gaining this information until the DM says the party's (l)earned it.

…But if you insist

While actual full-blown planar travel—à la the 5th-level Clr spell plane shift [conj] (PH 262) et al.—is restricted, rare is the DM that also restricts extradimensional spaces, yet each extradimensional space is its own demiplane. With this in mind, have the party enter one of its extradimensional spaces—I recommend an enveloping pit (Magic Item Compendium 159) (3,600 gp; 0 lbs.) or something similarly (ahem) spacious—and, while therein, cast upon a party member the 4th-level ranger spell implacable pursuer [div] (Spell Compendium 120–1), having the party member first lower his spell resistance (if any) then voluntarily forgo his saving throw. The spell's effect enables the caster for 1/hour per level to know the subject's

location as long as the subject is moving, no matter where it goes on the same plane. Even if it leaves the plane, implacable pursuer tells you what plane the subject creature went to. (121)

Then have that party member exit the extradimensional space. The caster of the spell implacable pursuer should then learn immediately what mysterious plane the party member has ventured to.

Note that the party'll probably tip off the DM to this plan as the party'll have to acquire a scroll of implacable pursuer since I doubt that the party includes a level 14 or 15 ranger (or a level 7 or 8 assassin or consecrated harrier but I guess there could be a level 8 mystic ranger). And, once the DM is tipped off, I suspect that this otherwise surefire method, too, will fail capriciously.

Much more expensive will be a scroll of the 8th-level Sor/Wiz spell discern location [div] (PH 222) and casting the spell on a party member. The spell's effect

reveals the name of the creature['s] location (place, name, business name, building name, or the like), community, county (or similar political division), country, continent, and the plane of existence where the target lies. (ibid.)

Thus, unless "direct intervention of a deity keeps [the caster] from learning the exact location of" the subject—an unlikely possibility given the restrictions on spells dealing with deities—, an answer should be forthcoming. However, the DM may nonetheless lawyer even this, saying that when the spell reveals "the plane of existence where the target lies" the spell informs the caster that the plane is This plane right here… the one you're on now. If given such an answer, try to avoid doing anything rash.

By RAW, how much information is "tells you what plane the subject creature went to" actually required to provide? I feel like it'd just say "that one over there" and point at the exit. — user2357112, Sep 25 '17 at 22:42
@user2357112 I've pretty much quoted the extent of the rules, so make of them what you will. You're right, of course, that the rules won't stop the absolutely committed from pulling jerk moves, so that leaves the player to ask himself Is this the thing that finally causes me to leave this table? — Hey I Can Chan, Sep 25 '17 at 23:12

score 22 · Answer 2 · edited Jun 16 '20 at 10:23

You're probably in Ravenloft

Wish et. al. not working? Unable to leave no matter what? Even interplanar communication and divination acting up? There's exactly one published place like that (although even then KS: Planes should let you know what's up, as should Divinations cause revealing the location isn't usually something the people running the show avoid, but we'll just chalk those ones up to DM error), and it's the Demiplane of Dread aka Ravenloft.

It should be pretty easy to confirm or dismiss this by comparing the ambiance of your surroundings, random encounters, and any NPC groups you encounter to those one would expect from Ravenloft's fantasy-Transylvanian-analog horror setting. If this is the case you may want to mention that figuring out the fact the PCs have been transported to Ravenloft isn't usually one of the things the Plane or its denizens stop you from doing.

If you aren't, you are on the homebrew Plane of Rails

That is, your DM isn't gonna let you figure out where you are except by the exact method they have in mind. Any attempts to figure stuff out will just be met with increasingly problematic-for-gameplay house rules. Your options there are to either A) accept that your DM has arbitrarily decided you aren't allowed to do this and stop trying and, more importantly, stop discussing it to forestall explanations that cause other parts of the game to break or B) talk to your DM about what's going on, out of character, and try to reach an agreement that way.

Now I'm torn between my next homebrew cosmology's interdimensional nexus looking like an airport (because, obviously, they're planes) and a railway yard (because the only way out is to hop the next train to Plot City). — Hey I Can Chan, Sep 25 '17 at 20:38
Ah, the Plane of Rails. The the most loathed of all prison planes, the place desolate of will, the realm from which there is only one escape (unless your name is Henderson)... — GMJoe, Sep 25 '17 at 21:04

score 6 · Accepted Answer · edited Jun 16 '20 at 10:23

The Psionic power Know Direction and Location will give you an answer...

...even though that answer may not always be entirely useful. The power is described as follows in the SRD:

You generally know where you are. This power is useful to characters who end up at unfamiliar destinations after teleporting, using a gate, or traveling to or from other planes of existence. The power reveals general information about your location as a feeling or presentiment. The information is usually no more detailed than a summary that locates you according to a prominent local or regional site. Using this power also tells you what direction you are facing.

Using this power prior to making a Knowledge (the planes) check with astral caravan grants a +2 bonus on the check.

Note that since you get a "location" based on a regional and/or local site, that still may not tell you what plane you are on, specifically, though the types of names may give you clues. This might be a nice compromise between your DM handing you the answer, and refusing to tell you.