For Passager and its sequels, Hobby and Merlin, Yolen provides an unusual and interesting perspective on the figure Merlin, a literary character so potent that he has appeared in the literatures of many nations in many languages, although his origin is in Britain. King Arthur, with whom Merlin is closely associated, has had his childhood told and retold from many perspectives, usually with Merlin playing a part in his becoming King of the Britons. Yolen says that it was Merlin's father-like relationship with Arthur that inspired Passager, although she first depicted Merlin as Arthur's mentor in the short story "The Dragon's Boy" (1993). In Passager, Yolen tells of the child Merlin and some of the experiences, that shape the odd, mysterious, and menacing yet vulnerable figure that he will ultimately become.
A fearful pair of women abandon a seven-year-old boy in the woods, leaving him with only the clothes he is wearing and whatever he has been taught about gathering food. Will he be found by the people of the woods and given sanctuary by them? Will he become an incoherent boy of the woods, uttering animal sounds and knowing nothing about human companionship? Given that Passager is the first book of The Young Merlin Trilogy, one realizes that the boy must be Merlin. Yet, how does the dirty, naked boy who remembers few words and seems lost to human companionship become the great wizard of the tales of King Arthur? Therein lies the tale.