Magnum, P.I. (1980)

Magnum has been hired by a woman to act out some of her rich, bored sister's fantasy dramas, concocted from 1930s Dashiell Hammett films. Although growing to enjoy the world of fantasy, Magnum has a hard time keeping up with the eccentric woman, and when he finds out that her husband is a wealthy, infamously jealous and bad-tempered business man, he decides to cut his loses and finish the arrangement. But he is just informing the girl that he is calling a halt to his participation, when they are attacked by real thugs, and soon after the girl is poisoned. With the woman still caught up in her world of fantasy, Magnum must thrust himself back into reality to find out just what is really going on...