Deadly Rivals (1993)

An introverted laser-research scientist journeys to Miami to attend a weapons conference and finds himself romantically entangled with a gorgeous model. A confirmed bookworm, the scientist is puzzled and flattered by her interest. He becomes more puzzled when FBI agents contact him and have him steal important documents. Later, another FBI agent appears and tells him that the two previous agents worked for the enemy. Meanwhile a gangster working for a prominent Miami Don, has kidnapped the model and is torturing her because he thinks she may have information about her sister, a mob courier who took off with a fortune in smuggled emeralds. More mayhem ensues as he tries to rescue her and finds himself further entangled with the FBI, the treacherous courier, and the mob. The story is narrated by the kidnapper who tells his complex tale in prison.