Arcane begins against the backdrop of the stark contrast between Piltover, the City of Progress, and Zaun, the Undercity.

Two sisters, Vi and Jinx, live in Zaun with their adoptive father, Vander.

Living in poverty, Vi and her friends occasionally raid Piltover to survive.

One day, a major accident occurs while they are robbing a scientist's home in Piltover, causing tensions between the two cities to reach a breaking point.

As Piltover intensifies its crackdown, resentment among the residents of Zaun grows.

The ambitious Silco emerges, sparking a power struggle within Zaun, just as Hextech—a new technology combining magic and science—is introduced for the first time.