When Kate Sullivan, a journalist, and an old friend of Thomas, Rick, and T.C. from the Vietnam days, arrives in Hawaii and asks for Magnum's help in tracking down an international assassin, Magnum learns that the target is a Prime Minister visiting from a small island republic. However, Magnum becomes suspicious of Kate's determination for getting the story.

Magnum wakes up in the hospital with amnesia and the Ferrari totalled. As he tries to put the pieces of the puzzle together, he remembers investigating the case of a missing woman. But, the girl turns up murdered and Magnum is considered the prime suspect when his baseball cap is found at the murder scene.