The Girl Who Saved The King of Sweden

 The Girl Who Saved The King of Sweden by Jonas Jonasson

Nombeko, 14 years old, intelligent and ambitious, works as a latrine cleaner in South Africa before becoming cleaning lady for, and prisoner of, a nuclear engineer working for the government. She spends years plotting her escape, using the time to learn the principals of nuclear science (because her boss is manufacturing bombs), and how to speak Chinese (because it's the native language of some of the other servant/prisoners).

As a servant she is ignored by most of the politicians and other influential visitors to her bosses office, but she observes and listens and files what she learns away for future use. When assigned the task of shipping a bomb to Israel, she uses the opportunity to escape, but then through a bureaucratic mix-up the bomb is sent to the wrong address and is delivered to Nombeko, herself when she settles in Sweden.

In Sweden she gets involved with a man named Holger and his brother, who is also named Holger and whose burning desire is to bring down the Swedish monarchy. The radical Holger's girlfriend shares his belief that the monarchy is corrupt and must be destroyed. The foursome have a series of unlikely adventures with an assortment of characters including Swedish and Chinese officials, Swedish royalty, and the girlfriend's flaky aunt who believes herself to be a Countess. Through all of this they cart the bomb around, trying to keep it hidden and looking for a way to be rid of it. 

It's a quirky story, full of improbable circumstances and coincidences that in the end make some kind of weird sense. It's fun and funny, but not weightless; you end up rooting for all these characters. I liked it.