The Drawing of the Three is the second book in The Dark Tower series. It was published in 1987. The subtitle of the book is RENEWAL.
The book begins less than seven hours after the end of The Gunslinger after The Man in Black has described the Gunslinger's fate using tarot cards. Roland Deschain wakes up on the beach of the Western Sea, where he is suddenly attacked by a strange, lobster-like creature, which he dubs a "lobstrosity." He kills the creature but not before losing the index and middle finger of his right hand, and most of his right big toe; his untreated wounds soon become infected. Feverish and losing strength, Roland continues to trek north along the beach, where he eventually encounters three doors. Each door opens onto New York City at different periods in time (1987, 1964 and 1977, respectively) and, as Roland passes through these doors, he brings back the companions who will join him on his quest to the Dark Tower.
The first door (labeled "The Prisoner") brings Eddie Dean, a young heroin addict who is in the process of smuggling cocaine for the drug lord Enrico Balazar. With the help of Roland, Eddie manages to avoid being caught in the act of smuggling the drugs and defeat Balazar and his goons in a fire-fight. Since Eddie was headed deeper into addiction (at the hands of his brother Henry Dean) or prison (at the hands of the government), or worse (at the hands of his drug lord), he decides to throw his lot in with Roland, although with deep misgivings that he occasionally gives vent to in the form of angry outbursts.
The second door (labeled "The Lady of Shadows," so called for her multiple personalities and metaphorically, multiple shadows) reveals Odetta Holmes, a black woman who is active in the civil rights movement. She is wealthy and missing her legs below the knees after being pushed in front of a subway car. Odetta is completely unaware that she has an alternate personality, a violent, predatory woman named Detta Walker. Roland and Eddie are forced to contend with both of these personalities when Odetta's body is forcibly abducted into their world.
Instead of revealing a new companion, the third door (labeled "The Pusher") instead reveals a new adversary for Roland: Jack Mort, a sociopath who takes sadistic pleasure in injuring and killing random strangers — and the man responsible for the head trauma that created Odetta Holmes's alternate personality, the loss of Odetta/Detta's legs, and the death of Jake Chambers. Mort's murder of Jake led to Jake's appearance in The Gunslinger. Roland's decisions while dealing with Mort are crucial to later events in the series. The encounter results in the death of Jack Mort and the fusing of the personalities of Odetta and Detta to form a third woman, who will thenceforth be called Susannah. Although the Gunslinger does not bring "The Pusher" with him into his own world (as might be guessed based upon what has happened regarding the previous two doors), his quest for the Dark Tower is not lost, because Roland does draw his third. His third is Susannah Dean; the result of Odetta and Detta's fusion of minds.
Through his actions both in his world, and in Eddie, Susannah, and Jack Mort's world, Roland saves Eddie and Susannah. He saves Eddie by curing him of his addiction and bringing Susannah, whom Eddie loves. He saves Susannah by helping her fuse her former personalities, Odetta Holmes and Detta Walker, into a stronger single personality, Susannah Dean. Both owe their lives to Roland, and Roland is acutely aware that he may need to sacrifice them to reach the Tower.
Each of these people is essential for Roland to continue his quest. They are all part of a ka-tet, defined as "one made from many" and "sharing the same destiny."