In the Underground Empire Jeojeojeo, located beneath the Overworld, the 17th Great King unexpectedly abdicates. A competition is announced to determine the next ruler. Jet, a Rank-A prisoner and dethroned half-prince, enters the contest at his father's behest. To win, each participant must protect a "Prince's Token" amidst fierce competition from other underground inhabitants. Jet discovers that his assigned "Token" is a perceived loser, adding an unexpected challenge to his quest for the throne.