Lost Family Heirloom, help needed

Pelagia, the secret key keeper for the Wierno Loyalist hideout in Wysepka has been asked by Tamara to be on the lookout for any potentially significant individuals who might come through tow. She wants Pelagia to find out if they can be trusted, and if they could prove valuable allies. To fulfill this request Pelagia decided to put up posters asking for adventurers to find a lost family heirloom of hers. See, once upon a time Pelagia's family were some of the most loyal servants of house Wierno, and so they even had their own crypt, the family was known as Yablonskev. As far as Pelagia knows nobody knows about her crypt, except for that group of adventurers who are set to leave town in the coming days of course.
With the competition from a contesting group Pelagia offers a high price for whoever can go and bring back her heirloom. She will give whichever group bring it back a whole 150 gold. But she asks that this heirloom must be kept safe and be without damage upon it's return.
Now there is a catch, see Pelagia doesnt exactly know what the heirloom is, all she knows is that her father always said "At the heart of our ancestral crypt it lays, like a beating heart it pulses with the waves beneath. Oh a truly beautiful thing it was".
The crypt of her family is far north, even beyond the Castle of Katrach. The journey there will take many days, and there are no real roads there, so she advises travellers to take with them ample gear. She also remarks that any loot found in the crypt is theirs to keep, and truthfully, she doesn't much care if she disturbs their crypts, to her they are little more then ash anyhow.
When the adventurers leave, Pelagia will offer them a companion for the road, Bob, her cat. If they refuse she insists, and if they still refuse, she grumpily accepts, but sends Bob to follow them anyways. Pelagia can communicate with Bob, and depending on how they act on this quest, she may consider giving them further work, to find out if they could become allies of the Wierno Loyalists