Stephen 'Gruey' Grucock was another in the long line of mischievous schoolboys - headed by Jennings and William Brown (Just William) - who was always involved in harebrained schemes and unlikely escapades. Mostly, Gruey's exploits resulted in direct confrontation with his arch-enemy, 'Nidgey' Jackson, a situation that usually caused problems for Gruey and his two pals - 'Wooly' and an Asian girl, 'Quidsy' - owing to Gruey's bad luck and sheer incompetence. A second series, bearing the punning Gruey Twoey title, aired in 1989, with Quidsy out of the picture and two new friends for Gruey - Annie and 'Supermouse'. Otherwise the hi-jinks were much the same as before.

Both series were written by former teacher Martin Riley, who took the name of Gruey from one of his former pupils but based the character on an amalgam of boisterous boys he had encountered.