This is a fast-moving thriller in which Monika Lundgren, a young Swedish secret agent, foils a plot to smuggle nuclear weapons from the ex-Soviet Union into southern Africa.
The story opens in Stockholm with the attempted assassination of Kurt Carlsson, a senior Swedish minister. Carlsson is chairman of a United Nations committee, working to prevent nuclear weapons getting into the hands of terrorists. Monika sees a bright flash of light when Carlsson falls, but hears no shot.
Monika follows the trail of an English football team, Millham United, who are touring Scandinavia. She joins them on a ferry to Finland and enjoys meeting Bruce, one of the team’s supporters, but finds out little.
Back in Stockholm, Monika’s boss, Anders Blom, tells Monika that James Chapman of MI5 in London is arriving in Sweden to help with the case. Monika and Chapman dive together in the water near where Carlsson was shot and Monika finds a crossbow bolt, used to shoot Carlsson.
Blom and Monika are convinced that a terrorist group is using the Millham United football team to hide its activities, so Monika visits the Millham United club in London. There she finds a meeting taking place between members of a right-wing Swedish group and the leader of a South African right-wing group, Adolf Vitjord.
Blom sends Monika to South Africa to await Vitjord’s return. She successfully tracks Vitjord down and narrowly escapes being captured by him. Monika escapes to Mozambique where she is pursued
by Vitjord’s men and is helped by the friendly Mozambicans, Cabinda and Amelia.
Back in Stockholm once more, Monika prevents another assassination attempt on Carlsson and discovers that the would-be killer is Bruce, the man she met on her journey to Finland.
The story concludes with Monika discovering a nuclear weapon on Millham United’s coach. She is attacked by Vitjord, and Chapman appears, not to save her, but to help Vitjord, with whom he has been working for years. Vitjord reveals that Bruce is his son. Monika is injured, though not seriously, and Blom’s men finally come to the rescue.