Instructions
Go to South Bank Village and speak to Dantro's wife. She tells you that she could use some Semclam Shells for her patient.
Look for glints in the water around the banks of the nearby river. These are two of the shells. Find three more at the river near the Bank of Nebra.
Give the shells to Dantro's Wife. She will now request some Nebralim, and says her husband has some. Head to the Outpost and speak to Dantro.
Look around the crates after Dantro tells you to search there. You will find one canister of Nebralim; a second one is in the northeast part of this area. Go back to South Bank Village and give these to Dantro's wife.
Take the boat across the river in South Bank Village to search for Valeblossom Dew -- the next item on the woman's list. You must search in the Broken Sands area to the northwest. Look for branches with pink leaves sticking out of the cliffs. You can find three specimens of Valeblossom Dew here.
Return to Dantro's wife and give her your haul. Hand over the Great Serpentskin next. You will already have this item for completing the "Marauder in the Mines" section of the game. After you give Dantro's wife this last item, she tells you she expects the patient to recover.
Return to the village after some time has passed in the game and speak to Dantro's wife again. She tells you that the patient is behind the house. Speak to him and you will receive the Barheim Key.