The President's Daughter (Sean Dillon Series #6)

Twenty years after his affair with a beautiful Frenchwoman in Vietnam, Jake Cazalet finds out he has a daughter. He must keep it a secret—but years later, when he is President of the United States, someone discovers the truth.

Ans when his only child is kidnapped by a terrorist group, he must count on British operative Sean Dillon and FBI agent Blake Johnson to find her.