Magnum is hired to protect "The Soul of Soong," an ancient Chinese vase, until it can be delivered to its owner.
A guy meets a marital arts assassin to sell the location of a priceless vase, The Soul of Sung. The assassin gets the information and kills the guy. The deadly marital arts assassin can kill in the blink of an eye. The case moves from there as the assassin tracks the vase and Magnum is hired by a Chinese antiques dealer who currently owns the vase.
Magnum flies (on TCs helicopter) to the island where the antiques dealer lives and has the shop. She runs the shop with another. She travels back with Magnum to the estate where she awaits the time to transfer the vase. As they leave the shop, the assassin visits the store and starts to destroy the shop as he tries to get the new location out of the other shop dealer. The shop dealer talks and then is killed.
At the estate, Mai Ling talks to Higgins in her native tongue. Higgins wants to view the vase, but due to its value, she does not want to open it. It is locked in a safe.
The assassin tracks down TC; TC is attacked but not killed since there are other people around.
Magnum and Mai Ling visit with Rick. During the visit, Magnum gets word that TC is hurt. Rick and Magnum tend to the wounds and TC explains how the guy moves and acts. It seems that Mai Ling is aware of who the person is as she mentions Tong. She realizes she must get to her uncle. She explains the history of the tong (assassin).
Magnum and Mai Ling travel to her uncle. There she plans to stay until her cousin arrives and she can give the cousin the vase. As Magnum drives away, his seventh sense kicks in and he returns to the uncle's place. Mai Ling was kidnapped and the ransom was the Soul of Sung.
Magnum works out a place with TC and Rick's help to save Mai Ling and get the vase back. Mai Ling was left on the beach in the hot sun, drugged and dehydrated. As he helps her, Rick and TC are tracking the vase. The assassin breaks the vase and Rick and TC get away.
Higgins looks at the broken vase pieces and realizes it is a reproduction and not the original.
As the story continues, Magnum realizes that Mai Ling was not planting flowers at a cemetery, but rather was hiding the vase. He and TC head there; the assassin and Mai Ling's cousin are also there. A fight ensues. Magnum gets his gun and the tong starts to use his deadly hands. Magnum shoots.
The vase is returned with the cousin. Mai Ling is safe.
- Tom Selleck as Thomas Sullivan Magnum IV
- John Hillerman as Jonathan Quayle Higgins III
- Roger E. Mosley as Theodore "T.C." Calvin
- Larry Manetti as Rick Wright
- Susie Elene as Mai Ling (credited as Suesie Elena)
- Lee de Broux as Duffy (credited as Lee DeBroux)
- George Cheung as Choi (credited as George Kee Cheung)
- Yankee Chang as Han Ling
- Lee Woodd as Koko