Yuri Kirov is an officer in the Russian Military Intelligence.
When we meet him he holds the rank of Captain-Lieutenant and is assigned to a new, secret submarine operating off the coast of the state of Washington and in terrible trouble inside American territorial waters. If it were not for this trouble which could result in the total loss of life on the vessel stuck on the bottom of the sea and unable to move, we would never have known of this man and we would not have been able to follow the adventures of this highly intelligent and exceptionally resourceful man.
Thanks to his influential grandfather, an admiral, and no thanks to his perpetually absent father, Kirov had received an excellent education and had done quite well, including becoming fluent in English. He had joined the Russian navy out of love and respect for his mentor grandparent and "After earning his commission, Kirov received a year of postgraduate training in electronics and communications at a technical institute in Moscow. Then spent sixteen weeks training with a naval dive unit based out of Sevastopol on the Black Sea." He became "some kind of underwater Intel expert".
Kirov was very happy with his life in the submarine fleet, considering the crew with whom he has been serving his family, and would not have sought any change to that. Unfortunately, to save his submates he has to make certain decisions which will change his life completely. That change will include his agreeing, eventually and reluctantly, to work for his new home, America. Unfortunately for him, his former home, Russia, has not forgotten about him and how useful he can be, either, so they, too, will come to call for help.
When Laura Newman, the woman who would soon become the most important person in Kirov's life, first sees him, she sees a man
"standing at least an inch over six feet, he had a muscular build, slate-gray eyes, and dense jet-black hair cut short. His angular face sprouted several days' worth of black stubble. She guessed his age around her own - early thirties [she was close, he was 29]".
Kirov shows over and over just how resilient and resourceful he can be. Considering the things both Russia and America want him to do, he needs to be.