This quest was marked obsolete by Blizzard and cannot be obtained or completed.
Kill the trogg leader, Grawmug, and his two guards, Gnasher and Brawler, and then report back to Captain Rugelfuss in Thelsamar.
My ploy worked. It appears that these beasts in Loch Modan are following the lead of a chieftain named Grawmug. Grawmug is heavily guarded, however. Two of his most elite guards, Gnasher and Brawler, never leave his side.
If you feel yourself worthy, <name>, I want you to lead the assassination mission on Grawmug and his two thugs inside this cave. Go! I'll free myself from these bindings and meet you shortly.