A secret spy organization, unknown to the world.
Its secret is using children.
Because children will never be suspected of being secret spies that have been trained in espionage, hacking, fighting, firearms, spying, are they?
CHERUB uses children to infiltrate drug circles, street gangs, terrorists, religious cults, even other secret spy organizations.
CHERUB only selects the top 1% of children, even those that are considered to be geniuses. They must have the drive, will, determination to prevail in perilous situations, even when others would despair. They must demonstrate high mental and physical fortitude, being strong where others would succumb to temptation, peer pressure or when being tortured.
They are CHERUB.
CHERUB uses the differences in T-Shirts to demonstrate their experience. Red-Shirts are for those who have not undergone training yet, typically children under 10. Pale Blue are for those about to or are undergoing training; 100 days of continuous, intense training to help CHERUBs understand what they are about to go through as they enter missions. Once they have succeeded in lasting the course, They are now Grey-Shirts, and are considered agents of CHERUB. They can get promoted throughout their time as a CHERUB, from Gray (Basic agents) to Navy, as they perform exceptionally under intense conditions, to Black, who have demonstrated excellence over several missions. Finally, as they graduate from CHERUB, they are awarded the White Shirt, as a remembrance to their service, their possible sacrifices as a CHERUB.
And this is the story of Alex Ng, the fastest Black-Shirt in history.