The temple was rumoured to hide a secret and Fukien, the head monk at Qlon, revealed that a way to defeat Neclord was hidden in the cave. Allowing Tir and his companions to enter the cave, Inside the cave is a very long maze. At the end of the cave they found the Star Dragon Sword who, upon being awoken, transported Tir and his party some 300 years into the past when the Village of the Hidden Rune was attacked. Presumably, this time-travelling phenomenon is where the cave derives its name from.
In the cave there are some strange looking walls which hides a secret passage that leads you to chests that contain valuable items like Hugo's War Scroll and Window's Window Rune were also hidden in this winding system of caverns. You can also find Crowley who has isolated himself from the world. You also can find the Old Book Vol. 2 here.