The events of Winter Hawk transpire over a few days in which the Soviet Union will launch into Earth orbit the first in a series of space-based laser battle stations, the existence of which they have kept a closely guarded secret.

The Americans know of the weapon because a Soviet technician named Philip Kedrov has been supplying them information, operating under the code-name "Cactus Plant".

He also surveils Kedrov, suspecting that the Americans will try extracting him before the launch of the laser weapon, although he has no way of knowing that the mission will be flown by Mitchell Gant.

Gant narrowly avoids destruction over Afghanistan only to be captured once he reaches Baikonur and tries to extract Kedrov, falling into the hands of KGB officers who had been surveilling the turncoat engineer.

Priabin soon learns the truth, but he is unable to warn Moscow because an Army-imposed, pre-launch security lockdown has cut Baikonur off from the rest of the world.

Realizing that the army will soon eliminate him as it has other obstacles, Priabin is forced to save Gant in order for the American to fly them both out of Baikonur along with evidence of "Lightning".

Led to believe that the KGB drove his son to suicide, but suspecting his other officers nonetheless, Rodin keeps Priabin in his own custody, even as he orders a massive hunt for Gant.

Emotionally unhinged by his son's death, and his wife's suicide immediately following it, Rodin is unable to keep Priabin from escaping before the laser weapon has been successfully placed in orbit.

With the help of Kedrov, Priabin finds the covert tracking station the army will use to control the laser satellite, and sabotages its orbital uplink.

Thomas' recurring British characters — Kenneth Aubrey, Peter Shelley, Patrick Hyde, Giles Pyott — do not appear in the story.

Unlike previous books, the events of this story are separated by a much wider interval, as the setting is clearly post Cold War.