Clayman awakened as a true demon lord. The fight between Rimuru and the puppet master continues, but the difference in strength is very evident. The battle and its aftermath bring profound changes to the Ten Demon Lords.

Yuuki asks Rimuru to investigate the Kingdom of Coleus, where a battle for succession has pitted the kingdom's two princes against each other. Rimuru launches a covert operation to sneak into Coleus and find out what's driving this conflict.