sentences:  At the same time, the CIA tries to liberate Markov, but the agents are killed by Markov's assistant Natassia, who really works for the KGB, and under the pretense that he is taken to Sweden, Markov is instead transported to a castle near Kotlas, Russia, where he is placed under the supervision of an American traitor named Ableman.However, Markov has hidden the formula for his invention within the text of a romance novel, with only him knowing the method of how to decode it.Nadia is taken to the fortress and is reunited with her father, and with her presence Markov starts completing his formula, unaware that he is marked for liquidation once he is finished.