On a commercial flight to Montenegro, an F.B.I. man, James Vine, notices a fellow passenger, an attractive 25-year old woman named Sandra Perkins. But he also notices subtle attempts from the part of the flight attendant to slip a poison pill into the passenger's drink. James Vine spills her drink and saves her life. However, the G-man finds it strange that all members of the flight crew leave the cockpit and head to the rear section of the plane. Minutes later, 4 parachutes are seen opening outside the aircraft. James realizes the crew bailed-out of the plane, leaving the aircraft on auto-pilot. James rushes to the cockpit to find it empty. He explains to Sandra that an attempt is being made on her life and that he will try to fly the aircraft himself, recalling his wartime pilot training. While James is bringing the aircraft into landing position, Sandra is manning the communication devices to contact the airport's control tower. After the landing, James and Sandra give statements to the local police with regards to the incident. Later, they check-in the hotel and James tries to find out from Sandra about her life in order to determine who would want her dead and why. When Sandra tells James that on her upcoming 25th birthday she will inherit the hefty sum of 72 million dollars and that in the case of her death the money will go to her uncle Henry Perkins in Rome, he puts two and two together. In the following days, many attempts on Sandra's life are made but James is always nearby to protect her. A local crime syndicate, run by Gérard van Looch, nicknamed 'Giant', is also after Sandra's inheritance. Its methods are more sophisticated. The gang, operating under the guise of a religious order out of a medieval castle, uses the services of a mind-control psychic who brainwashes its victims into becoming obedient slaves. The monks wear yellow habits but underneath they carry machine-guns. Their boss, the 'Giant' already has a small army at his disposal as well as a harem of brain-washed obedient sex-slave beauties. Sandra could be next.