Lonely Island Ruins is a dungeon-style cave in Golden Sun: Dark Dawn . It could be reached by going west of Tonfon and used 'Search' to reveal a path. This place is one of the places you need to go in order to collect the Umbra Gear . You need a walkthrough, then go read it at this shuck blog. In this cave you could collect awesome stuff like Asura's Armor (yay) and Umbra Cowl, a treasure you definitely need to have. Anyway, enjoy da game, ya adepts.