#1 | 29.01.1973Episode 1 (The Mysterious Death on the Underground Railway)
Polly Burton assists in soving the case of a grl found dead on a seat of an underground train.
#2 | 05.02.1973Episode 2 (Five Hundred Carats)
Inspecor Lipinski investigates the theft of a 500 carat diamond.
#3 | 12.02.1973Episode 3 (Cell 13)
Professor Van Dusen, the 'Thinking Machine', boasts that he can think his way out of a prison cell. When he is locked up he is given the chance to prove that he can escape by the power of his mind alone.
#4 | 19.02.1973Episode 4 (The Secret of the Manifique)
Laxworthy and two friends secure the safety of the plans for the first torpedo to be used by the French navy.
#5 | 26.02.1973Episode 5 (The Absent-Minded Coterie)
Valmont has to help break a ring of counterfeiters.
#6 | 04.03.1973Episode 6 (The Sensible Action of Lieutenant Hoist)
Lieutenant Holst of Copenhagen has to help a Russian countess who claims her brother-in-law aims to kill her.
#7 | 11.03.1973Episode 7 (The Superfluous Finger)
Professor Van Dusen must find out why a young woman had a perfectly healthy finger cut off by the eminent surgeon Prescott.
#8 | 19.03.1973Episode 8 (Anonymous Letters)
In turn-of-the-century Vienna, Dagobert Trostler investigates a poison pen case.
#9 | 26.03.1973Episode 9 (The Moabite Cypher)
Dr Thorndyke has to decypher a code to stop a plot to assassinate a Russian Grand Duke.
#10 | 02.04.1973Episode 10 (The Secret of the Foxhunter)
William Drew of the foreign Office investigates an unusual crime.
#11 | 09.04.1973Episode 11 (The Missing Q.C's)
Charles Dallas is led into a strange and sinister adventure in the aftermath of a sensational murder trial.
#12 | 16.04.1973Episode 12 (The Looting of the Species Room)
Gold disappears from the strongroom of the RMS Oceanic and its purser, Mr Horrocks, tries to discover what has happened.
#13 | 07.05.1973Episode 13 (The Mystery of the Amber Beads)
Hagar the Gypsy sets out to prove that Detective Sergeat Grubber is wrong about who killed Mrs Arryford.
#19 | 04.03.1973The Sensible Action of Lieutenant Holst
#20 | 11.03.1973Folge 20 (The Superfluous Finger)
#21 | 18.03.1973Folge 21 (Anonymous Letters)
#22 | 26.03.1973Folge 22 (The Moabite Cypher)
#23 | 02.04.1973Folge 23 (The Secret of the Foxhunter)
#24 | 09.04.1973Folge 24 (The Missing Q.C.s)
#25 | 16.04.1973The Looting of the Species Room
#26 | 23.04.1973Folge 26 (The Mystery of the Amber Beads)