Toni and Terri Trent (both played by Betta St. John) are a successful American singing duo who have just arrived in London.  When Terri disappears, Toni and Brady join up to find her ….

The first few minutes sets up the story.  Terri, looking out of her hotel-room window, witnesses a murder.  She reports this to the hotel manager, Stavros (Philip Leaver), but since he’s an accomplice this wasn’t the wisest of moves.  When the murderer,  Andreas (Wolfe Morris), realises that she can identify him, Terri needs to disappear.  Given that Andreas has a very prominent scar, Terri is able to describe him very easily (perhaps choosing someone more nondescript would have been a better idea).

The plot of this one isn’t quite watertight.  We later learn, thanks to Brady’s invisible shadowing, that the dead man was executed by his (unnamed) government.  That’s reasonable enough, but since they balk at killing Terri exactly what are they going to do with her?  In the short term she’s kept prisoner on an island, with Andreas and others in attendance, but that clearly can’t go on forever.

When Terri is reunited with Toni, the underlings then decide it would be better if both girls were disposed of.  If only they’d killed Terri to begin with then they wouldn’t have had all this trouble ….

But the meeting of the two sisters at least allows us to enjoy a touch of split-screen photography (pretty impressive) as well as a few scenes where St. John shares the screen with a double (not so good as her double seems to be about a foot shorter!)

Brady’s pretty invisible (sorry) in this one.  His dialogue is kept to a minimum as the other characters drive the plot.  He does have a few good moments though – an invisible punch-up at the end and an amusing sequence earlier on when he fails to hail a cab (one of the drawbacks of being an invisible man).

The Decoy makes a change from the spy stories of the last few episodes, but it’s another entry which struggles to rise above average.