The series centred around Marjorie Dawe and the two Riddlers (small humanoid creatures, portrayed by puppets, whose main aim in life was to "riddle things out") named Mossop and Tiddler (female, but voiced by Mike Gallant), who inhabited her garden at Riddleton End. Tiddler was not the latter's real name, but a title given to young apprentice Riddlers: once they achieved full Riddler status there would be a special (graduation type) ceremony, at which they would be given their 'real' name. Tiddler's training included being told stories by a Riddlestone, usually one of 'Ees-Up's Foibles'- she would then have to 'riddle out' the moral of the story.
When Tiddler had achieved full Riddler status (by getting the morals of twelve stories correctly) she chose to be called Tiddlup at the ceremony. Marjorie wanted to go to the ceremony but was told by Mossop that only Riddlers and Tiddlers could go as it was a Riddler law. In order to go, she became a tiddler and started to study as a tiddler.
Other characters featured in the show included Marjorie's neighbour, Mr. Montgomery Grimley (a gardener), and several other riddler characters - including another tiddler known as Middler, Mossop's brother Glossop, and Eesup, a story-teller. Marjorie's sister Monica was also featured as a recurring character. Many of the plots featured in the series revolved around the male characters making mistakes which would then be solved by the female ones.
- Marjorie Dawe: Victoria Williams
- Mr. Grimley: Peter Llewellyn Jones
- Monica: Sally Sheridan
- Mossop/Middler: Richard Robinson
- Tiddlup/Glossop/Eesup: Mike Gallant
226 episodes were produced and broadcast during the series' nine-year run. For much of its run, The Riddlers was produced by Ian Fell and directed by Chris Ryder (later a series producer). Later series were directed by Ann Ayoub. The executive producer was Chris Jelley.
All episodes were written by Rick Vanes (whose previous work for YTV included Puddle Lane and Mooncat). Ees-Up's Foibles stories were written by Shirley Isherwood. Neil Innes provided the music and songs featured. Puppeteer for Middler and Mossop, Richard Robinson, created the puppets and provided illustrations for the Ees-Up's Foibles stories. David Baker was assistant puppeteer series 1 through 6 and Garry Rutter for the show's last three years.
Many of the programmes were recorded in Yorkshire Television's studios on Kirstall Road, Leeds, although some later episodes were filmed on location. Five VHS releases were issued by Video Collection International, one DVD was issued by Kids Club and several tie-in books were published.
An episode from the fifth series was broadcast on the CITV channel on 6 January 2013, as part of a weekend of archive programmes to celebrate CITV's 30th anniversary.
- Series 1: (15 mins) 26 editions from 2 November 1989 – 10 May 1990
- Series 2: (18 mins) 26 editions from 15 November 1990 – 23 May 1991
- Series 3: (15 mins) 29 editions from 12 December 1991 – 4 June 1992 & 26 November 1992 - 7 January 1993
- Series 4: (15 mins) 18 editions from 14 January 1993 – 13 May 1993
- Series 5: (8 mins) 30 editions from 7 September 1993 – 4 January 1994
- Series 6: (8 mins) 20 editions from 12 January 1994 – 2 February 1994
- Series 7: (8 mins) 25 editions from 7 September 1995 – 7 March 1996
- Series 8: (8 mins) 25 editions from 12 September 1996 – 13 March 1997
- Series 9: (8 mins) 25 editions from 9 September 1997 – 27 August 1998
(These are in the correct series order as listed by ITV)