A British agent is found dead in suspicious circumstances. Now rumours are circulating of a plot to steal a huge consignment of diamonds belonging to a Middle Eastern Sheik. The diamonds are part of a deal to secure oil for Britain and Sir Gerald Tarrant, head of a British secret service organisation, needs some specialist help to prevent the plot being carried out. He decides to 'set a thief to catch a thief' and persuades former criminal Modesty Blaise to come out of retirement, along with her right-hand man Willie Garvin.
Modesty Blaise, by Peter O'Donnell, was adapted from the novel of the same name by Stef Penney.
With an original score by Goldfrapp's Will Gregory, arranged by Ian Gardiner, and performed by the BBC National Orchestra of Wales, conducted by Ben Foster.
A BBC/Cymru Wales production, produced and directed by Kate McAll.