The story picks up only hours after The Gunslinger ended.  Roland Deschain of Gilead wakes up while being attacked by creatures from the sea.  He escapes them, but not without serious wounds, wounds that will bother him throughout the story.  He fulfills his destiny laid out by the Tarod-cards of the Man in Black, and will have to drag three from wherever they are to Roland's world: The Prisoner, The Lady, and Death.  At least, that is what he thinks he has to do.  Towards the end of the book we really find out what "Drawing of the Three" means.

When he finds the first door, labeled "The Prisoner", he is unaware of what is behind, and discovering what is makes him very uneasy at first, for the first he sees is the Earth, seen from several miles high.  Roland soon finds out he is not really there, he is in the mind of someone who looks down from the window of an airplane.  While poison from the sea-creatures that attacked him travels along his blood-stream, Roland travels along with Eddie Dean, and figures out the rules and possibilities of the passage he uses - for a passage it is, a passage between worlds.  He understands he should take Eddie Dean to his own world, but he also sees that Eddie has some unfinished business, a business that is starting to go wrong as soon as the gunslinger enters Eddie's mind.

The gunslinger helps Eddie, whose prison is not around him, but in what Roland understands as being an equivalent of devil-weed: his heroin-addiction.  Eddie in turn helps the gunslinger with medication from our world.  But when the dust settles and they travel in Roland's world towards the second door, Eddie's addiction, his sense of being lost and homesick, and the love he is growing for this odd person, can only result in a fierce inner conflict.  The second person Roland will get doesn't make the next days any easier...

This book is just laying the foundation for whatever comes next.  Roland's quest is too big for him alone, and the force that steers him towards the Dark Tower gives him companions.  More than that, Roland the last gunslinger discovers gunslinger-qualities in each character drawn from a world that is so strange yet familiar to him.

We don't see very much of the environment, in fact we see almost exclusively a beach as far as the eye can see, and we travel only a handful of miles along it.  In this story we don't explore the land, not yet.  The real strength of this book is that it mocks the rules of the genre here and there - Roland is a few body-parts lighter right from the first chapter for example, or the strong leader is physically the weakest throughout the book - and most of all that it builds a few wonderfully rich characters, and very promising interactions.  No clean-cut polished people that enter the world big-eyed, but scarred and hurt living beings, with real feelings and unresolved matters in their minds. 

The Drawing of the Three is several degrees stronger than The Gunslinger which, forgive me for saying this, is clearly from the hand of a beginning writer.  The Drawing of the Three shows the skills of one of the best story-tellers of our time, doing his best so his own magnum opus is set on the rails properly.  We still don't know what this Tower is, who Roland is, what is going on or why Roland needs to go to this Tower.  But after this book you will have to find out.