Young JOE WACHEERA lives on a small idyllic plot in rural Kenya with his loving parents. The area, however, is fraught with violence, and his father is gruesomely murdered before his eyes. Joe and his mother flee for their lives to Kibera, a large Nairobi slum, where his mother is forced into prostitution by an apparent pillar of the church, REVEREND MWELELI.
Determined to escape this horrifying situation, Joe does whatever he can to improve their lot. He puts together a gang of toughs, sets up an operation selling bhang (marijuana) to the community, and organises private tutoring. When Mweleli intervenes in a dispute between Joe and a local shopkeeper, Joe ends up working for him on a casual basis, serving tea to visiting business guests.
Joe overhears meetings between the reverend, a GENERAL KARIUKI, a British businessman SIR OSWALD HIGGINBOTHAM and others, who conspire to set up a people smuggling operation. Joe 'befriends' Kariuki and uncomfortably agrees to trade sexual favours in return for tutoring in banking finance and accounting. Unbeknownst to Kariuki, using his new found skills Joe regularly steals portions of Kariuki's ill-gotten wealth, hiding it away in London bank accounts.
Joe is now sixteen; he and his gang of toughs negotiate their way into joining the people smuggling operation, acting as assistants taking people to Juba in South Sudan. His mother marries and moves out of the slums. But then Kariuki discovers Joe's theft.
He confronts and tries to throttle Joe, who, almost by accident, kills him. Joe flees Nairobi and he and his gang join a smuggling operation taking refugees from Juba to Libya; part of the way through the journey Joe takes over the operation. Once in Libya, he and his gang are engaged by British security to rescue a kidnapped agent, which they do in the hope of gaining British citizenship.
Joe smuggles himself into London, illegally acquires a British identity and is employed as a messenger at Sir Oswald Higginbotham's financial advisory firm, though Higginbotham does not see or recognise him. With Joe's financial knowledge, and partly through stealing confidential information from Higginbotham's, Joe gradually sets up his own financial advisory business. It's then he meets Isabel Anderson, a kindred spirit with whom he has a passionate love affair. They dream of a future together but must first obtain a legal identity for Joe.
Before they can approach MI5 and what turns out to be the agent Joe rescued, however, he is accused of murder - committed by the British man whose identity Joe illegally assumed. He is jailed. Isabel employs a lawyer and Joe is freed. He then exchanges his knowledge of people smuggling for legal citizenship and a guarantee against prosecution for past misdeeds.
Joe and Isabel marry, set up a jointly run firm, including Joe's advisory business. Joe's mother dies, and they return to Kenya to see if Joe can reclaim the land stolen from his family years earlier. While in Kenya, MI5 requests he acts as a part-time agent to assist in prosecutions of all the people smuggling conspirators, including Mweleli in Kenya and Sir Oswald Higginbotham in Britain.
After a final confrontation with Kenyan security services over Kariuki's death, Joe is exonerated, is tempted but decides against a takeover of Higginbotham's, and regains possession of his family's land. He and Isabel set up a school for girls, in Nairobi, dedicated to Joe's mother.
