Summer, 1940. Hitler's army is advancing towards Paris, and millions of French civilians are on the run. Amidst the chaos, two British children are being hunted by German agents. British spy Charles Henderson tries to reach them first, but he can only do it with the help of a twelve-year-old French orphan. The British secret service is about to discover that kids working undercover will help to win the war. For official purposes, these children do not exist.

Late summer, 1940. Hitler has conquered France. Now he intends to cross the Channel and defeat Britain before winter arrives. A group of young refugees led by British spy Charles Henderson faces a stark choice. To head south into the safety of neutral Spain, or go north on a risky mission to sabotage the German invasion plans. For official purposes, these children do not exist.

Britain, 1941. The government is building a secret army of intelligence agents to work undercover, gathering information and planning sabotage operations. Henderson's boys are part of that network: kids cut adrift by the war, training for the fight of their lives. They'll have to parachute into unknown territory, travel cross-country and outsmart a bunch of adults in a daredevil exercise. In wartime Britain, anything goes.

APRIL 1941 With no European allies, Britain has to ship fuel, weapons and more than half of its food across the Atlantic from Canada and the United States. But slow moving cargo vessels make easy prey for packs of German submarines. Henderson and a team of young agents must go undercover to sabotage German U-Boat operations. If they dont succeed, the British people face starvation.

One of Henderson's best agents is being held captive in Frankfurt. A set of forged record cards could be his ticket to freedom, but might just as easily become his death warrant. A vital mission awaits him in France - if he can find a way to escape.

Spring, 1943. The war is turning against Germany, but Hitler isn't giving up. In a secret bunker deep in occupied France, scientists are hard at work on Hitler's latest deadly weapon: code name FZG-76. Back in England Henderson's boys will need to undergo advanced sniper training if they have any chance of infiltrating the bunker. Parachuting into occupied France, they track down a secret dossier filled with invaluable material and uncover the meaning of the enigmatic code.

Summer, 1944. As Allied soldiers prepare to land in France, Marc and his friends must destroy a battalion of German tanks that could halt the invasion in its tracks. The tide of war has turned against the Nazis, but desperation has made them more brutal than ever. Henderson's Boys' final mission will be their most dangerous. With food and weapons in short supply, survival is the biggest challenge of all.