Lewis's book has a complex structure because he chooses to explain the importance of the "blind side" blocking tackle and defensive linebacker in the game of football and because he weaves football in and out of the protagonist's story, which itself includes flashbacks. As a result, the narrative opens with a true story about National Football League quarterback Theismann and defensive linebacker Taylor. Quarterbacks have a side where they have no vision when they are initiating plays. This is their left-hand side if throwing right-handed, the right if throwing left-handed. If an opposing defensive linebacker approaches in this blind spot, on this blind side, then the linebacker, if not tackled, can block the play by taking the quarterback down and possibly gaining possession of the ball.
In 1985 Coach Parcells puts linebacker Taylor on the right-hand defensive line, which positions him to approach on Theismann's, the opposing quarterback's, blind side. Joe Jacoby, the left tackle meant to protect the quarterback's blind side, is sidelined and replaced by another player. As result, in the catastrophe that follows, Taylor tackles Theismann and a pile occurs in which Theismann's leg is badly fractured and Taylor, reportedly, suffers severe claustrophobia (with what is now known about Traumatic Brain Injury in contact sports, it might be supposed that Taylor suffered a brain trauma as well as a triggering of his claustrophobia). Michael Oher, a massive high school student and the story's protagonist, was seemingly born to fill Jacoby's vital role of blind side protector left tackle.
Chapter 2 introduces Michael Oher, who was destined to follow in Jacoby's role, but does so through the person of Tom Lemming who is the acknowledged expert on high school sports stars. In Lemming's attempt to interview Michael Oher in 2004 to compete in the Army-Navy Game, we learn that there are unusual circumstances surrounding Oher when he won't speak, won't fill out the required forms and seems completely disinterested in the glorious sports opportunity being held out to him. The clock winds back in Chapter 3 and we find Big Tony sponsoring Oher's education at a private privileged Southern Christian school but we also find that Oher is absolutely lost amidst the world of books and learning because of his deprived and neglected background. Tutors are obtained for him and he starts to improve. It is during this time that Lemming meets Oher and, though he can't include him in the Army-Navy Game, he does include him in an annual report to college coaches.
With this background information, the story progresses to tell how Oher is introduced to the game of football and other sports and how the very wealthy Tuohy family chooses to introduce Oher into their household and care for him while providing him with extra tutoring. They eventually adopt Oher, since he had already become a beloved part of their family, so that, during the college bids for Oher's attendance, their monetary gifts and protection would be seen as family generosity rather than manipulations on behalf of their favorite university team. Not all goes smoothly however because the NCAA investigates whether Oher is being manipulated by the Tuohy's for their own personal gain and for the gain of their charitable cause, their old University alma mater (an odd thing to think someone might hold as more valuable than a human being's dignity and well being). Finally, Mr. Tuohy is able to convince Ms. Thompson that they are sincere because he ingenuously explains how embracing Michael Oher into their family would ruin them personally, with their one-time friends, socially and politically.
Under the care of Big Tony and the Tuohy family and with the assistance of Lemming, a young man's tragic nearly abandoned life becomes a success in something that he is built to do and that opens doors for him to make more of himself than he would ever have dreamed of becoming through opportunities in and help with education. A final flashback opens up more of Oher's life before being taken into the Tuohy family and reveals the lessons that Big Tony taught him.
... a boy came to stay the night [at Big Tony's] and never left. His name was Michael Oher, but everyone just called him "Big Mike." [Big] Tony liked Big Mike, but he also could see that Big Mike was heading at warp speed toward a bad end. ... Tony decided that as long as he was taking [his son] for a Christian education, he should take Big Mike, too.