The serial stars Langhorne Burton as the fictional detective Sexton Blake, and Mickey Brantford as his assistant Tinker.
[1] Mr. Stormcroft (Leslie Perrins) visits Blake after his father was murdered in their West End mansion, where many female guests are staying.
Arriving at the library, Tinker discovers a piece of silken cloth stuck in a corner of the chair, and Blake notices scratch marks on the desk.
Just as he begins to call the police, the villainess, Valerie Simpson (Marjorie Hume), renders him unconscious with a smash on the head, but her escape is thwarted by Tinker and the policemen who arrive to check on Blake.
Blake wakes up and tells Mrs. Stormcroft that Valerie is not the daughter of an old friend, but a Soviet agent named Nadia Petrowskaya.
[5] Viewing two films several decades after their initial release, Norman Wright judged Silken Threads "ghastly" and The Clue of the Second Goblet "a little better — just a little.