Civil servant Yor Briar has a secret identity: an assassin named the Thorn Princess. Lately, single women had been suspected of being spies, which was making Yor nervous. Meanwhile, Loid was searching for someone to play Anya's mother so they could attend the interview at Eden College. He just happens to run into Yor at a boutique. Anya reads Yor's mind and finds out that she's an assassin and tries to get Loid to ask Yor to play her mother.

Ostania's counterintelligence agency and national security bureau conducts spy hunts and keeps surveillance on its citizens to maintain peace within the country. They are also called the Secret Police and are feared. Yor's younger brother Yuri actually belongs to the Secret Police and is hunting down spies while keeping this a secret from Yor and others around him. One day, he suddenly shows up at the Forger residence. The Forgers, who are full of secrets, and Yuri, who has a secret identity, come face to face!

In order to prove to Yuri that they are actually a married couple, Loid and Yor are supposed to kiss. Loid is willing to get this done immediately for the sake of Operation Strix, but Yor can't do this sober, so she ends up downing a bunch of wine and gets drunk. Yuri sees his sister this way, also gets drunk, and is unable to make rational decisions anymore...

Why has Yor been coming home late every night, her hands covered in cuts? Why has Franky asked Loid to meet him under mysterious and urgent circumstances? These are two tales of misadventure while seeking happiness in Berlint.

Eden's legendary dessert finally appears! In order to obtain the macaroons that supposedly can make you into an Imperial Scholar if eaten, Anya and her friends race to get to them first.

After boarding the cruise ship, Yor began her duty as bodyguard to Olka and her son. Meanwhile, Yor's superior, Matthew, finds an assassin who is after Olka and her son.

The morning after the attack from the assassins and the bomb scare, the cruise ship arrives at the resort island. Loid and Anya meet up with Yor and the three enjoy a family vacation!