Kobato finds Osanai crying in the school hallway, but she runs away without telling him what happened. At the student newspaper club, a new mystery involving Berliner Pfannkuchen (jelly doughnuts) awaits him.

Just before a date with Osanai, Kobato runs into Kengo, who shares some disturbing news and leaves a strange message. Together with Osanai, Kobato tries to solve the mystery. However, shortly after, it appears that Osanai is in great danger.

To top off their summer sweets tour around the city, Osanai treats Kobato to a Tropical Parfait as thanks for rescuing her. Along with this delicious treat, Kobato is also served the whole truth about Osanai's kidnapping.

After a long conversation, Osanai and Kobato come to the conclusion that their agreement has failed – and with it, their friendship. From then on, they go their separate ways.

Urino begins writing articles predicting the locations of the next suspicious fires.

There will be a change of pace in the school newspaper. Kobato shows an interest in serial fires.

Urino has a plan to catch the arsonist in the act.

Urino's rules spark escalating arson; Hiyori supports him while Osanai gives advice as bonds shift.

Urino and Kobato both arrive at the site of the final fire.

Kobato explains to Osanai how he arrived at his conclusion about the arsonist’s identity.

Kobato remembers his encounter with Osanai when they were in middle school.

Kobato wakes up in the hospital and sees a box of chocolates with a message from Osanai.

In the hospital, Kobato thinks back to the circumstances around Hisaka's car injury in middle school.

Kobato and Osanai finally find out the whole truth and get help from an old acquaintance.