The Janus Effect

When Paul Bolard is eliminated from a poker tournament in Las Vegas, his opponent, Dr. Natalie Kelly, an ER physician at a nearby hospital, seeks him out afterwards to apologize for causing his demise. They end up in together in his luxurious hotel suite where, at the height of his orgasm, Paul's old heart gives up and he dies with a smile as it was the culmination of most men's dream to expire while making love to a beautiful young woman.
Except that, though his tired old body conks out, Paul's mind survives the ordeal and implants itself in Natalie's brain , using her body as a willing host. The next morning, when both realize what had transpired and despite the bizarre occurrence, they are able to accept their strange new reality and are eager to explore the reason for it. To their surprise, they quickly discover the cause of it in Paul's remote past and come to the conclusion that they will have to look for a suitable donor host for his mind that will free and allow him to be on his own.
Three days later they are fortunate to find a perfect host, who happened to be a rogue FBI agent and an executioner for the Al Qaida terrorist organization who was masquerading as a hotel security guard. Because of the horrible crimes this person had committed, Paul has no compunctions about eliminating him and taking his body as his new and permanent host.
And thus begins the adventure....