The underground tennis tournament is finally heading to the final match. The Campbell siblings that Loid and Fiona are up against are playing dirty, as they have altered tennis rackets as well as the staff helping them out. But the spy pair from WISE overcome one obstacle after another and Loid deals the final blow! But right after the match, the State Security Service finds out about the dossier and infiltrates the tournament...
Yes. The traces of special ink 
on the back here must be it.
.نعم. لا بدّ أنّها آثار الحبر الخاصّ هنا في الخلف
Ja, die Rückstände der Spezialtinte auf
der Rückseite lassen nur einen Schluss zu.
Sí.
Sí.
Oui.
Già.
É. Os vestígios de tinta especial
no fundo devem ser o código...
Да.