Sky Casino Arc

Sky Casino Arc (天空カジノ編,) is the seventh story arc in Bungo Stray Dogs and is the fourth story arc in the Decay of the Angel Saga. It focuses on Sky Casino as the main setting place of the Hunting Dogs pursuit and the Armed Detective Agency's plan on capturing Sigma who knows the page's location.

Synopsis
The Hunting Dogs continue to pursuit the other agency members and have gathered intel that the latter is heading to Sky Casino. Meanwhile, Atsushi and Kyōka, with the help of Lucy Maud Montgomery is also heading to the Sky Casino in order to meet the casino's manager Sigma and know the page's location.

Rescue of Mushitaro Oguri
Atsushi and Kyōka manages to infiltrate the government bank where Mushitaro is currently imprisoned. Upon meeting, Atsushi asks for Mushitaro's help since the agency was framed and Mushitaro tried to warn them about Decay of the Angel trap. However, Mushitaro refuses telling the two that he no longer has interest in the outside world and prefers to be just held captive. Kyōka mentions the word "manuscript"and Mushitaro agrees to go with them. Mushitaro tries different ways to distract the two, but these fail due to Kyōka menacing threat. Ango Sakaguchi from the Special Division for Unusual Powers arrive outside the government bank together with military forces. Upon seeing Ango, Mushitaro states that they need to hurry and reveals information about the Seventh Agency. The three manage to pass the building's surveillance footage thanks to Mushitaro's ability and successfully escape from Ango's radar.

They decide to steal a car and escape by going through the sewers; however, they were found by Ango and eventually cornered by him. In reality, Ango let them escape in order for Fyodor Dostoevsky to think that they were against each other. During the travel, Ango reveals that he has been communicating with Dazai and clears the misunderstanding and tells that he is not a part of the Seventh Agency. The group is then transported into Lucy's ability dimension. Ango reveals that he have used the Seventh Agency's services in order to get Dazai out from the Port Mafia and erase his past. Ango also tells them that he has been working alone to find the true culprit since he believes there is a spy in the government. As agreed, Mushitaro shares the information he knows about the Decay of the Angel and their goal to wipe out the nation.

They then proceed to have an infilration mission in order to seize the "page" with Lucy serving as decoy in order for the agency not to be spotted.

Hunting Dogs Investigation
The Hunting Dogs discuss about the status of their investigation - discussing about the group Decay of the Angel and the hostage incident that took place four days ago. Meanwhile, Ōchi Fukuchi visits the detained Yukichi Fukuzawa and orders him to confess. However, the latter tells him that the agency is innocent and the battle will be win by them. Tetchō Suehiro and Saigiku Jōno go to the café near the agency's office to gather intel. Jōno shows the store manager a picture Lucy and if she is involved in aiding the agency to which the manager tells him otherwise. Unfortunately, Jōno catches him lying.

Jōno pressures the store manager and later informing him that he is the terrorists' accessory after the fact, Jōno is confident that the manager shall confess the Agency's whereabouts in no time. However, Tetchō makes a deal to the manager that they will not be punishing the wanted fugutives and will not be holding charges against Lucy given that he tells where the agency is currently headed. The store manager confesses that they are headed to the Sky Casino.

Sky Casino Infiltration
Michizō Tachihara and Teruko Okura head to the Sky Casino. Upon entering the casino, the Hunting Dogs orders Sigma to shut down the casino in order to corner the agency. However, Sigma refuses and the Hunting Dogs are suddenly surrounded by the casino's guards, ordering the latter to leave the casino. An explosion suddenyly erupts at the casino's entrance. Meanwhile, Atsushi, Kyōka, and Lucy are stranded at the casino due to the explosion blocking all their escape routes, stating that it was how Dazai had it planned and reinstates their mission to capture Sigma.

Due to the commotion caused by the explosion, Sigma decides to kill the Hunting Dogs members for destroying the casino. Meanwhile, Tachihara sets off to catch the agency. While searching, he spots Atsushi entering a room wondering if the agency has a hideout. Tachihara immediately tails him, but fails to catch him. It leds him to a room and finds a hidden safe embedded on the door. He uses his ability to burst it open and finds coins inside of it. Witnessing that the Hunting Dogs find the coins which turns out to be bomb disguised as a coin, Sigma sets off the bomb contained inside the coin. However, Tachihara survived the blast shocking Sigma. Eventually, Sigma decides to use a drone aircraft in order to erase the evidence of the explosive coins' existence. Just then, Teruko comes in Tachihara's aid.

Battle at the Sky Casino
The drone aircraft sent by Sigma to kill Tachihara contains explosive coins, resulting to a more bigger explosion in the casino. Tachihara then shares his thoughts about the terrorists' plan to spread the coins through the global economy, eventually detonating them all at once, and killing people. Teruko decides to broadcast this conspiracy to the world and heads off to the central communications room but was stopped by the casino guards. Meanwhile, Atsushi and Kyōka commence their plan to fight alongside the Hunting Dogs to stop the Decay of the Angel' plot and prove that the agency are not terrorists. Teruko and Tachihara take on the casino guards. At the Meursault, Fyodor and Dazai is seen discussing about Sigma and the Sky Casino - revealing that Sigma has no past and that the Sky Casino wasn't built thirteen years ago but just eight days ago. Eventually, Teruko and Tachihara overpower the casino guards causing them retreat but was confronted by the casino's customers which turns out to be Sigma's deal to the customers in exchange for money.

Teruko and Tachihara manage to escape from the customers' sights thanks to Teruko changing her and Tachihara's appearance using her ability. They soon face Sigma in the communications room. Remaining steadfast in his personal mission to protect the casino, Sigma brings forth the Painless Gun and fires successive attacks on Teruko, determined to win against his opponent. Sigma furhter attacks Teruko using a directional resonance gun heavily injuring Teruko. During their battle, Teruko shares about the bodily price they pay for becoming a Hunting Dogs member and shows her unyielding tenacity to not lose to Sigma. Eventually realizing that he can't save both the casino and himself, Sigma plunges himself to fall down together with Teruko in an attempt to save the casino at least. Teruko struggles to break free, but she later kicks him to fall alone. Atsushi then saves Sigma.

Atsushi immediately tells Sigma the reason for saving him - to know the page's location through Sigma. Sigma eventually gives up after Ango's message and lets them ask what they want. Out for nowhere, Nathaniel Hawthorne shoots Sigma. Atsushi fails to capture and save Sigma due to the latter letting go from Atsushi's hand. Lucy saves Atsushi from falling and immediately transports him into Anne's chamber. Hawthorne is restrained thanks to Lucy's ability. Due to the failed mission, Ango considers it to be an utter defeat. Back at the Sky Casino, Tachihara looks up to find some terrorist information and finds a video footage of Atsushi revealing the truth behind the terrorist incident, he then suddenly destroys evidence describing it as a false intel. Dazai learns the truth from Fyodor that allying from the Hunting Dogs is impossible from the starts as it is easy to change reality. Teruko orders Tachihara to go back to the mafia in order to find the other remaining agency members. After some thinking, Tachihara then states that there is no way the agency are the terrorists due to his visit to Gin and Hirotsu at the hospital.

Impact

 * The Seventh Agency was introduced.
 * The Decay of the Angel' goal and structure and goal has been revealed.
 * Sigma was introduced.
 * Sigma and the Sky Casino's past were revealed.
 * Atsushi reveals that he knows about the page's location.