Mainly filmed on location in Ireland, where one car a day passes the pub, if you're lucky.
Baxter is sent by his bosses to investigate a dead frogman washed up on the beach. It was found by a young girl, Miss Howard (what was she doing there?), and a reporter and photographer just happened to be on the spot. There's a mysterious beardie in a bungalow who's employing the (female) photographer as a fellow spy. Is the dead man a double agent last seen in Berlin? Baxter and Miss Howard stay in the same rather staid hotel in the nearest town as they wait for the inquest. The reporter and photographer hang around, ostensibly on the scent of a story.
1963 wasn't a great year for fashion, and all the women wear frumpy styles, big coats and awful hairdos. Staff at the hotel and airport have very English accents. The only "Oirish" is attempted by a barmaid and the mortuary attendant. Everybody smokes all the time, and drinks all day. Miss Howard becomes a bit giggly after her tenth gin and bitter lemon.
The sound was so bad that I turned on the subtitles. Miss Howard in particular EMphasized one word in every sentence but died away for the rest. The subtitler gave up on an Irish barman in a lonely pub where the last showdown takes place. We shall never know what he was saying. However, we are helpfully told when the soundtrack becomes sinister, menacing or resolutive.
Overall, it is like a substandard Francis Durbridge enacted by the Charles Vance players (the worst amateur troupe I have ever witnessed). The music is the best thing about this dreary movie - with a few genuinely lovely Irish folk tunes at the beginning.