When he arrives in Fiji to spend his holiday with an old friend, the Chief is suspicious about news that his friend has gone to visit him in San Francisco. After sending for Mark and Ed to join him, Ironside himself promptly disappears, leaving the boys to put the pieces together themselves.

Whilst in London at a conference with the Chief, Ed witnesses an assassination, and promptly becomes the killer's next target. Meanwhile he and Ironside have to work with the local forces to find the assassin, but find themselves hampered by the Superintendent on the case, an old friend of the Chief's who seems to have a hidden agenda.