The Demon Lord Carrion has sent one of his Three Beastketeers, Phobio, on a raid of Rimuru's city. However, Phobio is quickly defeated when Milim meets his attack with her own. Rimuru and his subordinates then ask Phobio why he has come to their town.

The threat of Charybdis has gone. That night, Rimuru has a dream in which he sees Shizu teaching children at her school in the Kingdom of Ingrassia—a dream showing Shizu's lingering regret. To see her wishes through, Rimuru leaves the Jura Tempest Federation and heads for the capital of the Kingdom of Ingrassia. His first goal is to meet with the Grandmaster of the Guild, Yuuki Kagurazaka, who happens to be a Summon and a former student of Shizu's.