Caoimhe is out, drinking and dicing; she wears the skin from her belt but she wouldn't give it up or lend it out unless forced to do so.
Halie looks relieved to hear the "bad" news. "There's some kind of cave underneath the island, too small for me to enter. An otter could make it through easily, or a beaver."
"A beaver, eh?" Wallace says. "What kind of cave are you looking at, here? And you going to be able to show me where it is?"
(I assume Wallace is the beaver?)
"No kind of cave I've seen before. I will show you." She takes heartbeast form, and ask Dalla to use her Mastery of Animal ability to change the sea eagle into an otter (don't have my books to check the spell level on that, but I think she should be able to pull it off-- it's easier to change an animal into another animal of the same size than it is to turn a person into a much smaller animal). She'll suppress her Parma for the magic, the dive in and show the tunnel to Wallace.
((Yes, Wallace is a beaver, Drystan's familiar.))
Changing Halie's Sea Eagle form into an otter is Base 5 ("Change an animal into a different animal."). Range could be Touch (+1) or Voice (+2), Duration could be Diameter (+1) or Sun (+2). So we're looking at Level 15 (Touch/Diameter), 20 (Touch/Sun or Voice/Diameter) to 25 (Voice/Sun). I'm thinking more likely the Touch/Sun version, which would cost 4 Might Points.
So, Halie is an otter (for now), Wallace the beaver. What's the plan? Is she going to go in first and have Wallace bring up the rear, or is he going to go first? (Note that the Eurasian Beaver is not a small animal. Wallace is going on four feet long, plus the tail, maybe a foot and a half tall, and a little over a foot wide.)
Also, what are you going to do regarding being able to see?
Possibly a InTe version of True Sight of Air, to see through the dirt obfuscation? (No books til I get home from work.)
"True Sight of the Air: Lets you see clearly through all manner of obfuscation in the air nearby, including smoke, fog, and dust, even if the obfuscation is magical."
She'll fatigue herself to try and spont an Aquam version of that ("True Sight of the Otter"?), while within the +6 aura of Eilean Chon:
15+3In+0Aq+2Stam+6Aura+6=32, halved=16, which is sufficient.
She'll take a breather, and then just before we go in, if Wallace and Drystan allow it, she'll try to spont a touch/diam version of the same spell for Wallace. Same total, and the roll is higher than the previous one, so it'll work. Oh, but it has to penetrate because magical creatures can't lower their innate MR, so it probably doesn't work-- that'd be 5 pen if you round up from halving, or 4 if you round down.
Halie's True Sight of the Otter doesn't work on Wallace – not enough Penetration.
See, the problem isn't so much that the water is murky (well, it is for the first few feet), but that after a few feet there's just not any light up in the cave/tunnel.
The thing goes in for a couple of feet then angles upward for a few feet (and hits stale air) before it angles slightly downward again for a couple of feet, then "opens" into a, for lack of a better word, bulb-shaped space not more than three or feet long and a couple feet wide. Halie can feel something underneath her paws besides dirt, but in the pitch blackness, it's hard to tell what it is. Feels like small, flat, sharp pieces of stone.
Faerie eyes can see perfectly in darkness.
D'oh! Okay, she can see fine. Wallace, no so much. Since Halie has Faerie Sight, does that mean she's in front, or behind?
And the things on the floor of the space are small, parchment-thin shards of something fragile that shatter whenever you do more than lightly tap it.
She'd go first.
The shards-- "What does this smell like to you, Wallace?"
Once she gets his nose properly situated, he takes a few good snuffles. "It smells like dirt," he finally decides.
She bites her tongue on the "Dirt has a smell?!?" response, and instead say "Thank you. Doesn't look anything like dirt, though..."
She'll spont/5 some super low level InTe: "Is this some kind of mineral?"
((C'mon, he's a beaver...if you'd stuck a wood shaving under his snout, he could probably not only tell you what kind of tree it's from, but how high the tree was, what time of year it was cut down, and how old the tree was when it died! Now, if he had been a mole, on the other hand...
))
Not a mineral. I'm assuming that you're going to go the "Twenty Questions" route and keep sponting Intellego X until you get it, in which case the shard is Animal.
They have giant noses! It was worth a shot.
She'll also do a non-fatiguing InVi spont to see "Is this vis?"
Yes...each of the shards is vis. Went ahead and did Touch/Momentary/Group – even with the No Gestures penalty, her InVi is still enough to get that.
It is a poor Bjornaer without Subtle Magic 
I assume the cave has no other exits than the one we came in?
"Wallace, could you please go back above and bring me a blade of grass from the island's surface, so I can bring these out? These require a bit more study. I now wonder whether the Niseag has any offspring." If he does, she'll gather up the shards carefully, and prepare to Leap above.
Once on solid ground, she'll assume her Inner Heartbeast (for the slight Stamina increase, for the slight boost to spellcasting), and then fatigue herself to spont an Animal version of "The Whole From the Part" (InAn15): 18In+8An+3Sta+6Au+5=40, halved is 20. Penetration is irrelevant unless the shards themselves have MR (because the target of the spell is the Arcane Connection itself, not the being who shed it), so if these came from a beast, Halie should get a mental image of the creature they came from.
Not that you can see, no.
He does. Give me a Dex roll (quality die) to see how the shards fare.
The spell goes off, but you don't get anything from the shards. (Also, give me a Per roll).
invisiblecastle.com/roller/view/3502621/
Her Dexterity is whatever Dex an otter has; the roll itself is a 4, modified by otter Dex.
Perception check is 6+3Per=9.
She's able to gather most of the shards together without breaking too many of them.
Once she gets them up to the surface and gets a better look at them, they look almost like eggshells. Dirty, grimy, brittle eggshells.
She'll grab some empty pawns and fatigue herself to spontaneously cast a Touch range ReVi (base 10, +1 touch), moving the vis into pawn form. Re 5 + Vim 12 + Stam 2 + 6 Au + 6 = 31, halved is the necessary 15. (How many pawns is it?)
She'll then give one pawn to Wallace as thanks for his assistance, and then seek out Drystan.
"First off, I need to know where to deposit some vis I found. Secondly, I'm curious as to the form the vis originally took. These look like eggshells to me--" she holds up the shards that the vis was originally in-- "but Wallace and I found them in a cave underneath Eilean Chon. The entrance was narrow enough that I find it unlikely the Niseag could have laid these eggs; it was easy enough for me to make it through wearing the skin of an otter, but Wallace found it a tight squeeze. I wonder if, perhaps, the Niseag may have grandchildren. These shards are not an active arcane connection to any living creature, or I would have been able to visualize the beast... which leads me to wonder whether the offspring from these eggs may have been consumed by a parent."