In the twin shadows of Piltover, the city of progress, and Zaun, the abyss of chaos, the fates of the top locksmith Aiden and the elusive thief Shadow are intertwined because of a mysterious blueprint of the "Eternal Lock". They put aside their opposition and joined forces to solve the legendary ultimate mystery. However, what is inside the lock core is not the wealth and power that the world longs for, but the forbidden knowledge about the origin of the world's runes that was sealed with life by the ancient sages, a prophecy of destruction and a stern warning that can tear apart the foundation of the continent. Faced with the truth that could tempt mortals to fall into the abyss, Aiden and Shadow chose a lonely path: becoming the "guardians" of secrets. Aiden used the precision skills of a locksmith to build invisible defense barriers, while Shadow relied on the acumen and stealth of a thief to shuttle through the gaps between light and shadow, detecting any traces of anyone who would covet it. Their enemies are everywhere: the seemingly righteous lawmen of Piltover, the all-pervasive shadow mages of Noxus, the greedy alchemist baron of Zaun, and the ever-present temptation and whisper of knowledge itself. When the shadow of betrayal shrouded the shadow and the price of protection was engraved in Shadow's dying life, the rune knowledge seeping into her blood began to quietly erode her will. At the junction of light and shadow, are the guardians resisting external enemies, or wrestling with the darkness within? When the chains are forged by the guardians themselves, are they imprisoning the crumbling world or their own gradually lost souls?
