The plot of the game is classic fairy-tale fantasy: the princess Arminda has been captured by the Dreaded Dragon Droom, and held in his dungeon, while her suitor Prince Henry has been turned into a frog.

The user has to rescue Arminda, aided by a witch, a wizard, fairies and the ever-helpful Little Bit on the way.

After "Droom" he went on to write various software packages including "Albert's House", "Pond" and "Rainbow Stories", all marketed through RESOURCE.

Derek Allen also wrote sequels to the program: "Dragon Droom's Revenge" and "Stardust" (early versions were known simply as "Dust").

Many of his programs continued to be available for PC from Resource Education, which had become a private company based in Derbyshire.