Fourth entry in the Mike Shayne series. This one is based on a story by Borden Chase. The only similarity to the original Brett Halliday book series is the name Mick Shayne. The movie continues the running gag of Mary Beth Hughes appearing in each movie as a different character engaged to Mike.
This entry involves Nazi spies and industrial diamonds. This one is pretty good despite some lame humor.
Merle Garland (Mary Beth Hughes) is a beauty shop owner engaged to Mike Shayne (Lloyd Nolan). He returns from an out of town case only to find Merle is about to marry a con man.; He pulls a trick to stop that. She’s not happy and goes to his place and starts throwing things at him. She finally stops when the cops back Mike up.
Mike promises her he’ll give up the P.I. business and get a real job. He goes to an aircraft plant and is hired to keep an eye on the riveters. He’s not a snitch and turns it down but then accepts it when he finds out it involves sabotage.
On the way to his job word comes that a hundred grand worth of industrial diamonds have been stolen. The plant’s diamond cutter, Vanderhoefen, is found knocked out by the safe. Mike looks him over and after Vanderhoefen leaves tells the cops and the head of the plant Mr.Thomas (Addison Richards) that Vanderhoefen knocked himself out.
Mike follows him to a dress company. He pretends to be Colonel Lee, a buyer from Atlanta. Company manager Rudolph Hagerman tells him they close early on Saturday. Hagerman is actually a Nazi spy and the shop is a cover for a ring that sends stolen diamonds to a dress shop in Honolulu for distribution in Germany.
From the back room Vanderhoefen spots him and lets Rudolph know Mike’s real identity. Hagerman is informed that their usual method of hiding the diamonds in dress buttons is known. Mike searches the warehouse and discovers the scam. He’s caught after dropping through the skylight but manages a cartoon like escape.
He found a trunk labeled for a cruise ship to Honolulu. Hagerman tells Thomas about Mike’s sneaking around and that gets him fired. Still determined Mike scams Merle out of a thousand bucks so he can get a ticket on the cruise ship. He gets a cabin right next door to the one on the address label. Turns out the passenger is an old friend using a phony name. She’s Helen Shaw.
Mike and Helen are about to go into her cabin when from across the hall comes Juan Arturo O’Hara (George “Superman” Reeves). The three are having a good time with steward Nappy Dubois. He tells them what he found out about them when he unpacked their bags. They all have a few more laughs over that.
Somebody with a silencer is taking pot shots at Mike and missing every time. Mike goes into a cargo hold and searches a couple trunks. Nothing. Nappy has been keeping an eye on him after O’Hara asks him to since he’s interested in Helen. Mike and O’Hara don’t like each other. Mike,Helen (calling herself Connie) and O’Hara are in the cabin having a few drinks when a note is delivered to Mike. It asks all three to join in a scavenger hunt later that night.
Mike’s troubles really explode when he almost drowns. That’s just the start as more trouble awaits in Honolulu.
This is a decent entry if you forget the book series. Realize from the second entry on none of the movies are based on Halliday’s writings and you may find yourself having a good time.