To fight the guild, the Armed Detective Agency and the Port Mafia must work together...

Following this proposal by Atsushi, a top-level conference is held between Fukuzawa and Mori.

However, as the talks naturally breaks down, Dazai infiltrates the enemy's base to retrieve Q.

Sure enough, Dazai is immediately set upon by Lovecraft and Steinbeck.

Then, who should make a dashing entrance but... that man?!!

Dazai's wisdom, Ranpo's deduction, and Atsushi's courage will be put to the test!