The Glimmer is a cavern between the two cavern walls connecting the opal and ruby seas and the only entrance way between the islands of Plume and the Auron. It was previously sealed by The Fear for hundreds of years, until it was destroyed by Glock.
Due to the large size of The Fear, nothing was able to pass between the two caverns. However, after its destruction, the people of Plume and Auron passed through freely.
Lief, Barda, Jasmine and Glock fought The Fear at the trio's quest to gather the pieces of the Pirran Pipe. A cage was placed in the middle of the cavern, which Lief, Barda, Jasmine, and Glock used to distract The Fear. After numerous attempts to kill the creature, Glock stabbed his dismantled sword down the creature's throat, killing it. However, in the process, Glock was crushed and died, not before giving Jasmine his talisman. Once the creature's tentacles had cleared, light of every colour streamed through.