At an event to raise money for the children of Naples, previous stones are to be on display, attracting every jewel thief known to The Police, and perhaps one or two that slip in under the radar.
It's a pleasing thirty minute heist, not the most exciting episode, not a massive amount of drama, and a plot that felt like something that could have come from Chesterton.
The major plus here, once again, the characters and the acting. Patrick Troughton is always terrific value, he was cracking here, as was Brenda de Branzie as The Duchess, she was fun.
You do have to question the logic of the story, talk about alerting every jewel thief in town, don't try and apply too much logic.
We were made to wait to learn the identity of the fourth man, so there was a twist to wait for at the end.
There may not be any car chases or indeed any actual external scenes, but it does very much have an Italian flavour, which is enjoyable.
All in all, not a bad one.
6/10.