The Defense Four are detained to their homes for a week due to the events of the previous episode. Takayama receives a letter with the text "Today could be your last day." Takayama calls Sakurai for assistance. Sakurai does not answer so he instead calls Haruka. Sakurai spots Haruka on the way to meet Takayama in Akihabara. After seeing the letter, Haruka suggests the sender could be an accomplice of the bomber of the Ashio Line. They are interrupted by a JNR mascot, Tsubarail and move to a different location. Sakurai calls Takayama back but during their conversation, a gust of wind surprises Sakurai and her phone breaks when she drops it. Sakurai spots them again while walking out of the phone repair shop. She shoots Takayama out of jealousy. Haruka and Takayama mistake this for a sniper and continue running away from Sakurai, who they mistake for the accomplice. Sakurai is also tailed by a police officer for shooting a gun in public. Takayama stumbles and falls on top of Haruka after climbing a fence. They fall on a supply of cat food and are later surrounded by cats, lured by the smell of the cat food. Sakurai finds remains of Haruka's clothes and tracks them. Takayama and Haruka seek refuge in the Transportation Museum. Iida and Gonō find Sakurai out on the streets but they are interrupted as Gonō recives a call that the alarm system at the Transportation Museum was tripped. Thieves also seem to have broken in to the Transportation Museum but they are stopped by Sakurai. It is revealed that Takayama and Haruka met eight years ago in the museum when she was trapped in a closet. Takayama came to her rescue then. After the thieves are taken care of, they find out that the letter was just an advertisement for JNR Life Insurance.