[RPG] How do the Pass without Trace and Hunter’s Mark spells interact


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?

Best Answer

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.

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.