The protagonist of the book, who also happens to be its author, has a condition called pseudocoma, which means that he appears to be in a coma, because he is unable to move, speak or communicate verbally at all, but he is able to think, and to realize the severity of his own predicament, and also able to communicate by blinking his eyes. The condition did not manifest himself until he suffered from a stroke, which caused him to fall into a coma that lasted for almost three weeks. When he woke up he was mentally capable; he knew where he was, who his visitors were, who he was, but he was physically paralyzed aside from a limited amount of eye movement. His stroke seemed to come out of nowhere; he was traveling to work listening to The Beatles, and then after work goes to pick up his son to take him to the theater, but on the way there his mind and his vision seem to go blurry. He remembers wondering where his son has gone, and then everything else goes dark
When he first awakens, his mind becomes more active as his body becomes quite the opposite; he is also unable to process the information that medical staff are giving him about his condition, partly because he has never heard of pseudocoma before, and partly because hearing the details of the condition is almost too frightening to process. A wheelchair is brought into his hospital room but he does not connect the dots, wondering why it has been placed next to his bed.
Surprisingly there is a second patient at the hospital who is suffering from psudocoma. Bauby's condition is manifesting itself rather differently than his counterpart's, and differently to the text book cases that medical staff are more familiar with. He is able to turn his head, which is highly unusual, and this fact alone gives him hope, because he believes that it is a sign of his potential to recover from the condition completely. His goals are simple and few; he wants to be able to eat independently again - being French, he takes his food very seriously - and on a more basic level wants to be able to breathe without the aid of a machine. Perhaps once he has re-learned the art of independent breathing, speech may follow. He devises a plan that will help him to heal; he assigns each of his family members and friends a different part of his body to pray for, so that every body part is taken care of and nothing is forgotten or left out.
Physical therapy is difficult and frustrating. His limbs are moved by someone else, usually his lead physical therapist. He is losing weight and specifically losing muscle tone. Despite a complete lack of improvement in his body as a whole he is gradually increasing the sphere of movement of his head. His brain is still working just as well as it ever has, perhaps even more efficiently, because it has to. He comes up with a new way of communicating; he re-arranges the letters of the alphabet by degree of usefulness; the letter "E", which crops up frequently in French vocabulary, begins the alphabet, and the letter "W", which is used very seldom, is relegated to the end. His friends read out the re-ordered alphabet that he has created and when he hears the letter that he wants to use, he blinks his left eye (his right eye has been sewn shut, because it keeps watering). They then write down the letter. Slowly but surely, he spells out words, then full sentences, in this manner.
As he becomes more familiar with the hospital, Bauby begins to explore it more fully. When it was first founded it was intended for the treatment of young soldiers returning from World War Two, and then for the treatment of tuberculosis patients, when the disease was running rampant. Nowadays, though, the patient demographic has changed, and most of the people receiving treatment there are seniors. He also meets quite a few tourists, who are directed to the hospital after emergencies, such as broken limbs. He becomes fascinated with the way in which they are physically rehabilitated and starts to watch them for long periods of time, hoping that he will pick up some information that might help aid his recovery as well.
Although he has a decent enough relationship with his physical therapist, Baudry's deeper relationship grows with his speech therapist. It had been her idea to come up with some kind of workable code that he could use for communication and now he is beginning to work on regaining his actual speech with her too. He is becoming frustrated that he is unable to converse with his loved ones; he can listen, but cannot say anything in return. He also listens to his father on the telephone. Their relationship has changed because before his stroke his father was the weaker and the more infirm, and the author helped to care for him, but now, his father is far more able to care for himself than Bauby is.
Much of the author's thoughts relate to prayer and religious experience of one kind of another, and he spends much time pondering on the pilgrimage he took to Lourdes, home of Joan of Arc, and consequently a place of miracles for those who visit it. He sees a statue of the Madonna for sale and purchases it as a gift for his then lover, Josephine, even though they both know they are going to split up, but he is becoming very sentimental about the relationship and realizes that Josephine has always loved him. He also receives several visits from his ex-wife, Sylvie, with whom he has two children, Celeste and Theophile. They visit on Father's Day and take him to the beach where they play the word game hangman. Because he is so skilled at communicating in individual letters he is actually very good at hangman and for once he is able to feel equal to everyone else around him. However, he misses his old life, pre-stroke, and it lives within him like a physical pain. He has only been able to go to Paris twice since the stroke, but it is a painful reminder of the way that things used to be. Before becoming paralyzed he worked as a magazine editor, and on his first trip into the city he goes by the old office building where he conducted his old working life. He misses his old job, his old colleagues, his old life, and wants to cry like a baby, but a few months later, when he visits again, he is resigned to his new reality, and seems to have lost the ability to feel emotions like this. In Paris, the rumor-mill is rife with stories of his mental degeneration; people say he has turned into a vegetable, and so he decides to write a letter every month to friends and family so that this will be proof of his mental capacity To his delight, his friends and family write back.
Small victories seem enormous; as the summer ends, and the first signs of fall are evident all around him, he is pleased that he can now grunt songs, which he feels is due to the hard work of his speech therapist. He also has time to re-read the notes that they have made over the last months and wonders if it will make a book or if he is deluding himself.
