Brett Halsey is George Farrell, agent 077. (There were at least ten spy films made in the sixties having to do with agent 077, some explicitly titled as such, some not so, that starred several different actors in the role. In this one, someone writes `0-7-7' on a piece of paper during a casino scene. Clue!) Halsey is literally dragged out of bed, where he was entertaining a lady, and sent to Lisbon to find a missing scientist. He never does find him but it's a lot of fun anyway as he and fellow agent Terry Brown (Marilu Tolo) put the pieces of the puzzle together.
The score by Daniel White is pretty bland big band jazz stuff and is sometimes grossly inappropriate to the action, like having organ music as men with guns are chasing our hero. A good score is one thing this film lacks. There are a few gadgets used by both sides, some more successfully pulled off than others.
There's a fun sequence when Tolo finds a dead double agent in her hotel room and Halsey helps her get rid of him by taking him through the raucous party next door. There are some genuine laughs here. We never see the party, only hear it, but an extra treat is the unbilled cameo by George Nader as a drunk who stumbles into the bathroom and mistakes the corpse as a fellow inebriate.
The film runs a bit long, like this review, and culminates in a gun battle with really bad foley effects for the guns used by Halsey and Tolo. Anyway, I recommend this film by director Tulio Demicheli (The Killer Lacks a Name) as a good teaming of Halsey and Tolo despite its shortcomings.