WARNING:This is a complete story summary intended for parents or others who wish to know the contents of Hitler's Angel. It will contain spoilers. To see a spoiler-free summary and other details about the book please visit the review page.
A German boy recently escaped from Dunkirk and an Austrian schoolgirl living in London are recruited to retrieve a “package”, a young girl Angelika, from the convent in Germany where she is kept safe. For some reason she is vitally important to Hitler. Given new identities as brother and sister Otto and Leni Fischer, the children are given basic training for two weeks and are then parachuted into Bavaria, near to the convent where the girl is.
Their plan succeeds with only minor hitches and they bring the girl out of the convent at night, escaping on the nuns’ motor launch and then on bicycle to the nearest railway junction. Here, Otto insists that they take a goods train rather than the more obvious passenger train to Innsbruck and their rendezvous. The train takes them to Munich and Otto admits that this was his hometown. He arranges to meet the girls at the station for their onward train and then secretly visits his family’s apartment, only to discover that it’s now the home of a Gestapo officer who chases him and traps him in a blind alley.
The girls have spotted him on their way to the station and Leni knocks the officer out from behind. They take a train but Leni is upset with Otto for having brought them to Munich for personal reasons and with Angelika for having run out of the museum where they were lying low. A nosy woman gets in and their cover story is blown when she tricks them with specific questions about their supposed home town. Otto is bracing himself to shoot her with the gun he carries but the woman faints in fear before he has to decide whether or not he can pull the trigger. The children leave the train and hitch a lift in a lorry.
Meanwhile, Hitler orders his feared chief of security Reinhard Heydrich to ensure that the girl is safe. Heydrich arrives at the Convent just in time to discover that she’s gone. He spitefully forces the Mother Superior to write a note making out that guilt and remorse for failing in her duty had led her to suicide before he shoots her and leaves the gun in her hand, knowing that this would most likely result in her being denied a Christian burial. Working on the assumption that the girl had been taken away by an adult couple he orders troops to form a net around the area.
The children, meanwhile, are making their way back towards their rendezvous point. They tell Angelika that they are taking her to see her parents in Switzerland, while in reality she’ll be placed in the hands of the British authorities. She trusts them as though they were her own brother & sister and they feel guilty for having to deceive her and uncertain about what her ultimate fate will be. Slipping through the cordon of soldiers they take shelter in a cow barn for the night.
Hitler insists that his personal astrologer and diviner, Herr Staniak, help the search. By now, Heydrich has worked out that he’s looking for three children and is scornful of the physically unimpressive mystic. However Staniak does in fact determine the children’s location and armed troops are sent to the village where they’re hiding. Otto hears them coming and sends the girls away through the woods, remaining behind to cover for them. He holds off the soldiers, killing one of them in self-defence, and Heydrich himself for as long as he can with a stolen machine gun but is eventually captured and Heydrich starts to interrogate him ruthlessly, at one point driving the spike of an ice knife through his hand.
The girls return to help him and they escape in a motorcycle and sidecar, having booby-trapped several of the other vehicles. They make their way up the mountains and rest. While Angelika is elsewhere, Otto & Leni discuss her fate and Otto reveals that he had been given a cyanide pill to ensure that the little girl would not fall alive into the Nazi’s clutches. They reason that Angelika is a person in her own right and not simply a tool of the warring powers. He throws the poison away and they agree not to simply hand her over to the British.
Moving up the mountain, they come across an airfield from which they steal a glider. Otto flies it as best he can and they get far enough to crash on the Swiss side of Piz Buin in the snowfield. Heydrich and his troops, undeterred by international law, follow them there, shooting a group of farmers who attempt to stop them. The Admiral McPherson, the British commander meeting them, gets wind of where they are and sets off towards the same spot. The children climb higher into the snowfield for which they’re poorly prepared. The Germans deploy specialist Alpine troops but Otto finds a German equipment pack and fires a grenade from a launcher, causing an avalanche which buries the troops and which catches up with the children as they speed downhill on a makeshift toboggan.
The children survive being buried in the snow and make their way towards the nearest village. As they near the final bridge, Otto stays back to hold off Heydrich and the remaining Nazi troops while the girls make for the village. He is captured by Heydrich and Leni offers to exchange Angelika for Otto. Heydrich agrees but as he comes forward, Angelika triggers a hidden grenade which destroys the bridge. Heydrich is injured and Angelika falls to her death and is washed away. Otto and Leni escape to where McPherson is waiting for them having destroyed the Germans’ means of transport.
They dig a grave for Angelika (it’s not clear whether they recover the body or not) and Otto & Leni insist on the little girl’s significance as a human being, not merely as a bargaining chip between great powers. McPherson finally admits that they are right. As they are flown back to Britain the youngsters hold hands and reveal their real names to each other: Rebecca and Conrad. The Germans are forced to walk back up the mountain in the snow until they reach the German side. The diviner tells Heydrich that he is certain that Hitler is not Angelika’s father, hinting that her mother is someone important. He also mentions that he’d had a vision of Heydrich in Prague, a foreshadowing of the security chief’s death at the hands of a British & Czech group.