Issuriel knows of someone who can brew an antidote for the gwigael poison, but the components are so rare that it is only realistic to expect a single dose.
'I know of... an antidote. The ingredients are very rare... but....'
Issuriel winces, clearly in a great deal of pain. When she has recovered enough to speak, she weakly continues.
'I need an unmarked venom sac from... the same brood of spider, Saewathel, or Blackvenom... and a flower. The flower Sereglos grows upon untended barrows... in Mirkwood. It blooms only for a few days... in the year... and dies. There may not... be any remaining... this season....'
She gasps for air and is silent.
The Sereglos flower grows for a short span of time on untended barrows in Mirkwood. Unmarked venom sacs from Saewathel or Blackvenom spiders, of the breeds related to the spider that poisoned Mazog and Issuriel may be found throughout the Scuttledells, north of Ost Galadh.
Time is short: if the errand of the Hidden Guard is to succeed, Issuriel demands that you gather the components of an antidote to cure Mazog of the gwigael poison.
Issuriel is within the makeshift camp in the storage room Gadorgar, inside Ost Galadh, south of the Scuttledells.
You have found the rare ingredients for the antidote Issuriel mentioned and should return to her with them at once.
Barvessain is somewhere in Ost Galadh, in Emyn Lûm, south of the Scuttledells.
Issuriel has weakly asked you to find Barvessain, somewhere in Ost Galadh, and to get her to brew the antidote for the gwigael poison from the components you collected.
Mazog and Issuriel are both within Gadorgar, the makeshift storage room in Ost Galadh.
You now have a single dose of Laidhris antidote and must give it to one of the victims of the Gwigael poison.
Achardor is in Gadorgar, the makeshift storage room in Ost Galadh.
You have given the antidote to Mazog, and Achardor is not pleased.
Gruingalas is outside the door to Gadorgar, in Ost Galadh.
Archardor wants no one coming into Gadorgar anymore, in order for Issuriel to rest. He also wants the scouts recalled in preparation for the exchange of Mazog and has asked you to tell Gruingalas of these requests.