Mori, the leader of the Port Mafia, sends a letter to Margaret M. and Nathaniel H., threatening to destroy them and the ship they are protecting.

The leaders of the Agency and the Port Mafia negotiate an alliance. Meanwhile, Dazai and Chuuya face off against Lovecraft.

Tensions between the Detective Agency and the Port Mafia run high as they both scramble to save their own leaders while avoiding an all-out war.

The Detective Agency receives an urgent request from the government to investigate a series murders perpetrated by the same culprit.

Teruko goes head-to-head with Sigma. Tachihara rethinks the Agency’s innocence after re-infiltrating the Port Mafia.