To Kill and Then to Die Part -1 is the 7th chapter of Bungo Stray Dog series.
Dazai is kidnapped by a young girl wearing a kimono. The Agency isn't very worried as he can take care of himself. Yosano, the Agency doctor known for her sadistic treatments, asks Atsushi to go shopping with her. After they're finished, they get on the train to go home, but are soon threatened by a Port Mafia member, Motojirou Kajii, who hijacked the train and threatens to blow up the train if Atsushi is not handed over. Yosano and Atsushi decide to split up to defuse the bombs and kill the enemy if they encounter him. Yosano, heading to the front of the train, is taken out by a lemon bomb thrown by Kajii but recovers and faces off against him. Atsushi, heading to the back of the train, encounters a young girl in a kimono with a cell phone. Atsushi tries to warn her away but is attacked by her ability Demon Snow. She turns out to be a member of the Mafia named Kyouka Izumi, ordered to protect the bomb with her life. Meanwhile, Yosano is seemingly killed by Kajii.