As Mari and Kouzuki Yuki are working at their part-time job in Akihabara to earn money for a buzzer set, Shiki and Inoue arrive in the area to train themselves with a quiz bowl game in the arcade. They're battling against a player called "Second Lieutenant Chisato" when Ashiya shows up, and the pair finds out that their opponent is someone they know quite well. Then a strange, somewhat suspicious character approaches the group...
Once you know that, it's 
easy to do it in your head.
بمجرّد أن نعرف هذا، يصبح 
.من السّهل حسابها في عقلنا
Wenn man das weiß,
ist das hier Kinderkacke.
Cuando lo sabes, es fácil.
Cuando lo sabes, es fácil.
Alors, ça devient facile.
Una volta che lo sai, è facile farlo a mente.
Sabendo disso, é fácil
 calcular de cabeça.
то определить ответ легко.