The Paradox

A scientist from DARPA must pursue a colleague back in time to 1968 Vietnam, in order to stop him from altering history and  prevent the murder of her father.
The story is about Jennifer Stanley, a DARPA scientist who, after burying the ashes of her estranged father, learns that a colleague named Quan has replicated her time machine, and gone back to 1968 Vietnam to prevent the death of his father.
 
Jennifer follows in an effort to stop him from altering history, and soon meets her father as a young soldier. She discovers that Quan’s plan involves the killing of her father, disrupts the plan, but gets captured before she can return to the present day.