Spy Classroom Short Story Collection, Vol. 3 (light novel) -

Avian, the elite spy team made up of the top academy students, has run into trouble in the Fend Commonwealth, and their boss, "Flock" Vindo, realizes they might not make it out alive. As his companions fall one by one to the unexpected attack, what comes to his mind are his memories of the month spent with Lamplight. After the mission in Longchon, Avian suffers a crushing defeat at the hands of Klaus, and in the pursuit of revenge accidentally become stalkers!? Of course, Lamplight can't just stand by and watch, and the two teams soon descend into chaos. Sometimes fighting, sometimes challenging each other, these young spies live out their youth in a way only they can; this is the story of their unforgettable honeymoon.