"It's Supposed to be Thicker than Water" is the twenty-second episode of the popular 1969 ITC British television series Randall and Hopkirk (Deceased) starring Mike Pratt, Kenneth Cope and Annette Andre. The episode was first broadcast on 13 February 1970 on the ITV. Directed by Leslie Norman.

Jeff is hired by an elderly gentleman of the wealthy Crackan family and his butler Hodder to deliver a letter to his nephew Johnny, recently escaped from jail. The letter invited him to stay with his uncle at his large country manor and is united with the rest of his relatives who come to stay including his niece, a Spaniard and a Japanese man and an Irish vicar who are apparently related. However, when the Spaniard one arriving at the manor is pushed out of a window Jeff becomes suspicious. Soon after his death the next day, the nephew Johnny takes his car for a drive and is travelling over 60 mph when the breaks lock up and he runs out of control over a massive quarry mountainside, killing him. Later that evening at dinner, the Japanese man is poisoned after his meal and all the time the elderly estate owner seems the none the worse or the least bit shocked. Leaving them, Jeff becoming attached to his niece (pictured) takes her to a lodge to esacpe the troubles and soon after leaving she finds the Irish vicar in her room. With her the only one in the way of the inheritance of the estate she appears very frightened believing he will kill her. However, when Jeff returns to her lodge he discovers the vicar dead in his bedroom next door. By this time the niece had departed quickly.

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