There are thousands of them. Children. Aged between nine and sixteen. They come to Europe from the middle East and Africa, and now they are on the move across our continent – alone, with no adults to accompany them. A blot on European immigration policy. Of all people, minors whose young age should guarantee them special protection and speedy integration into the new society, slip effortlessly through the net of the inadequate security afforded by European asylum procedures, escape to wherever they can, and are easy prey for criminals both from their own home countries and from Europe. Since the beginning of 2014 at least two hundred thousand unaccompanied child migrants have managed to cross Europe's borders. But according to the authorities, at least ten thousand of them have simply vanished en route. These are children, and one estimate of unreported cases puts the figure at twice or even three times that. Who are these children, and how did they manage to make themselves invisible?