Spy Classroom, Vol. 1 (manga) by Takemachi

A GARDEN OF FLOWERS READY TO BLOOM In a world torn apart by war and ruled by intelligence, Lily-code name Flower Garden-is determined to become a master spy and help bring peace to the nation. So, when she's offered to join an elite squad that takes on Impossible Missions with 90 percent mortality rates, she's ecstatic...until she finds out that said "elite squad" is made up entirely of spy academy washouts, like her. But each and every one of them has the potential to change the world, and under the tutelage of master spy Klaus, it's time for them to bloom!