How do the Pass without Trace and Hunter's Mark spells interact?

Question

I was running what was supposed to be a one-shot recently, where the party was tracking some unicorns. The party's ranger used Hunter's Mark on one of the unicorns, who then used pass without trace. The party then decided to check on some nearby NPCs, except that they also wanted to call it a night, which is probably convenient for me.

The Pass without Trace spell description says:

A veil of shadows and silence radiates from you, masking you and your companions from detection. For the duration, each creature you choose within 30 feet of you (including you) has a +10 bonus to Dexterity (Stealth) checks and can’t be tracked except by magical means. A creature that receives this bonus leaves behind no tracks or other traces of its passage.

The Hunter's Mark spell description says:

You choose a creature you can see within range and mystically mark it as your quarry. Until the spell ends, you deal an extra 1d6 damage to the target whenever you hit it with a weapon attack, and you have advantage on any Wisdom (Perception) or Wisdom (Survival) check you make to find it. If the target drops to 0 hit points before this spell ends, you can use a bonus action on a subsequent turn of yours to mark a new creature.

The unicorns are probably going to be far enough away that the detection effects aren't really going to be involved. But the tracking part... Well, Hunter's Mark is definitely magical, but does a Survival check with Hunter's Mark count as magical? And how would that even work if Pass without Trace leaves no traces behind?

Answer 1

Hunter's Mark is a spell - spells are magic

So this negates the "... can’t be tracked except by magical means" part. So, the ranger can attempt to track the marked and only the marked unicorn and will have advantage on the check.

However, this still leaves the "... leaves behind no tracks or other traces of its passage" part. Which flatly contradicts the previous sentence: it can be tracked magically but it leaves no tracks. So what is the ranger following? Well, there's magic involved so how about we say the ranger can follow the disturbance in the weave or some other equally arbitrary BS to resolve the paradox WotC made for itself.

If it were me, I would have the unicorn make a Dexterity (Stealth) check (at +10 for the Pass without Trace) to set the DC of the check. Or maybe I would use a passive Dexterity (Stealth) check (at +10 for the Pass without Trace) because it gives the players slightly better odds.

Answer 2

No, you can't track creatures via your Hunter's Mark if Pass Without Trace is active on it.

Pass Without Trace says:

can’t be tracked except by magical means

I believe this is meant to encompass things like Mind Spike, which simply says

you also always know the target's location until the spell ends

Hunter's Mark simply gives you advantage on specific Perception or Survival checks, but that doesn't count as magical means. It's simply a nonmagical activity enhanced by magic, not a magical means by itself. Furthermore, there has to be something for you to track, which isn't possible since the target "leaves behind no traces".
Note that the PHB states on page 7:

In cases where the outcome of an action is uncertain, the Dungeons & Dragons game relies on rolls of a 20-sided die, a d20, to determine success or failure.

If the target leaves no tracks, then the DM won't (or at least shouldn't) call for any kind of check to "track" it in the first place. Hence, getting advantage on an imaginary check doesn't really help here, similarly to how expertise with a skill is useless if you're not also proficient.

If there are no tracks, it doesn't matter how hard you look, you won't find any.

Similarly, spells like Enhance Ability or Skill Empowerment wouldn't allow you to track a creature that is under the effects of Pass Without Trace.

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That being said, going by RAF, the better choice is probably to rule that tracking is possible.

In the situation you described, your party tried to track a unicorn. If you don't allow them to track the unicorn, it will feel to your players like a scripted "F*** you, don't touch my plot". Obviously, that's not how you want your players to feel.

Therefore, in the end, I think it's probably better to allow them to track the unicorn, even though according to my interpretation of the rules, it wouldn't work. This way, your players may fail or may succeed on the roll, but either way, it will feel fair to them, because they were allowed to do something that feels like a creative use of spells.

Answer 3

TLDR

• I do not fully agree with either Dale M's answer or PixelMaster's answer.
• Both of those spells are magical; i.e. the spell classification.
• Pass without trace simply adds the condition that no trace is left behind from the caster's party.
• Hunter's Mark mystically marking the target makes the target still traceable.

I will not wholly restate the spell descriptions, but lets take the situation in hand as you initially state it.

First, the hunter uses the spell Hunter's Mark. This has placed a mystical mark on the desired target. The target is now magically marked. The additional bonuses the hunter receives regard attacking the target for bonus damage and finding the target if they lose track of it.

Then, the target uses the spell Pass Without Trace. Now the target, and its party within 30ft, no longer leave any tracks or traces behind as well as gaining a boost to stealth checks. Unfortunately for the target it can still be tracked by magical means, such as Hunter's Mark.

From this point, so long as the hunter (not their party) can see the target (not the target's party) Pass Without Trace has no effect in shielding the target from detection. The remaining members of the target's party are fully shielded from detection since Hunter's Mark only mystically marked the one target.

Since the spell Pass Without Trace allows the target to leave no trace or markings behind if the hunter loses track/sight of the target it is possible the target will safely disappear. There would be no tracks or markings for the hunter to follow to find his marked target. Seeing the mystical mark placed on the target is the only way to find the target again.

So long as the spell Hunter's Mark is active (max duration has not been reached) the target can be seen by the hunter; even if the hunter loses sight of the target for a moment since the mark would be visible once again as it came back into view.

Obviously, should either spell end the other active spell gain all the previously negated effects the expired spell was countering.