From the wastes of Siberia to the intrigue of the imperial court at St. Petersberg, 1916, the Third Doctor, Jo and Liz are involved in the machinations of the mad monk Rasputin.

As history plunges onward inexorably, the Doctor's companions realize that history books can lie. But the Doctor can see the threads that hold all time together -- can he and his companions escape the depravities of this decadent Russia without unraveling the history of Earth?