A small, specialized team of Allied commandos must infiltrate a heavily fortified German-held Greek island to destroy a pair of massive, impenetrable long-range guns. The protagonist, Captain Keith Mallory, leads a group of five experts tasked with a near-impossible sabotage mission that requires navigating treacherous terrain and evading constant enemy surveillance. The narrative follows a linear, high-stakes progression where the team's survival depends on their ability to adapt to shifting tactical constraints and internal betrayals. The story emphasizes the physical toll of guerrilla warfare and the psychological pressure of operating behind enemy lines with no hope of reinforcement.

Critics have long praised the work for its relentless narrative speed and the vivid creation of tension throughout the mission. The Sunday Times noted that the execution of the plot could hardly be bettered, highlighting the author's ability to maintain a high pitch of action. Readers and reviewers alike consistently point to the book's power in handling descriptions of combat and the psychological weight of the characters' decisions. The story remains a standard for the military thriller genre, recognized for its ability to sustain suspense from the opening pages until the final confrontation.