After Baretta busts a small time numbers racket his girlfriend is shot and killed. He looks to come up with a plan that will allow him to seek revenge while making sure he stays on the right side of the law.
After Baretta's childhood friend Eddie is killed, he takes on the obligation of a pregnant widow who is addicted to smack. He "kidnaps" her in an attempt to wean her off drugs to prevent the baby's being born addicted as well. His CI helps Baretta get justice.
Baretta meets a parole officer friend (John Shockley) returning from Mexico. Just after telling Baretta that he had seen a former parolee alive and well (in spite of being declared a suicide by drowning a few months earlier), Shockley is the victim of a deliberate hit-and-run. Baretta encounters official resistance to reopening the case, a befuddled grieving mother and a violent gangland attempt to find the "dead" woman and her accomplice.
Thugs hijack a drug shipment in Mexico, killing a guard and loading it onto trucks en route to Los Angeles. Baretta realizes that the drugs are destined for an old mobster and puts him under constant -- and obvious -- surveillance. It's so obvious that the mobster gets to know Baretta and even to create a semblance of friendship with him. By the end of Act Four, the mobster has served up his nephew (who was the driving force behind the robbery) to Baretta for arrest. Baretta is grateful, but in the tag he and the mobster sit on the mobster's front porch -- jointly waiting as the trucks roar up Interstate 5, getting ever closer to the mobster's imminent doom.
Baretta's current lady is a messed-up photographer. After a bust of counterfeit money being sold for a half million dollars, the real money is nowhere to be found--except by the lady photog. Baretta is suspected of the grab, pursued by the criminals, and hassled by his bosses. When his girl suddenly packs up to go, Baretta finally gets it, but he is almost too late!
Going undercover as a flamboyant hippie named Ragtime Billy Beaches, Baretta flies to Los Angeles to investigate a beautiful woman, married to a rich doctor, who was murdered.
Baretta's partner (Michael Parks) accepts a bribe during a setup by the police commission, and because of interference by a careless cop who yearns to be a novelist, Baretta could go down with his friend.
The title's "Secret" could involve who killed a mob boss (blamed on a lowly hit man), kept by Terry Lake, a mysterious woman with mob connections played by Margot Kidder, who Baretta goes undercover to investigate.
A wealthy District Attorney (Michael Murphy) calls his childhood friend Baretta to investigate his brother's missing wife. But the brother/husband doesn't seem very concerned.
