to protect Petra, and take on a rather adult responsibility.

The next day I tried to send thought-shapes to Petra. It seemed to me important for her to know as soon as possible that she must not give herself away. I tried hard, but I could make no contact with her. (ch 9)

Petra is too young to protect herself, and too young to understand what is happening to her.  David must look out for her to keep anyone else from finding out about her, but since she is so strong she is also a threat to all of the telepaths.

It is Anne’s choice that causes all of the telepaths to have to flee though.  When she marries a normal man, everyone is in danger.  She loves him, so she chooses to tell him.  He cannot accept it, and Uncle Axel has to kill him to protect all of the telepaths.  It doesn’t work.  They are found out.  David and Rosalind flee with Petra.

On the run, David experiences many adult situations.  His love for Rosalind is developing.  He has to have a parent-like relationship with young Petra.  He tries to protect Rosalind from his uncle’s less-than-pure intentions. 

David has become hardened and matured.  He is no longer the little boy he was.

Certainly Chapter 1 when David befriends Sophie and catches a glimpse of her feet causes the child David to find a discrepancy between what he has been taught and the truth as he experiences it. Consider how he thinks about it at the end of Chapter 1:

Clearly there must be a mistake somewhere. Surely having one very small toe extra - well, two very small toes, becuase I supposed there would be one to match on the other foot - surely that couldn't be enough to make her "hateful in the sight of God...?"

The ways of the world were very puzzling.

David begins to question and secretly doubt the rules and culture of his world. Of course, his befriending of Sophie and the discovery of her genetic "deviation" foreshadows his own discovery.

Chapter 4, with Uncle Axel's stern insistence that David and the others promise never to talk about their "gift" to others represents another milestone in David's development:

There had been no acknowledged, co-operative policy among us. It was simply as individuals that we had all taken the same self-protective secretive course. But now, out of Uncle Axel's anxious insistence on my promise, the feeling of a threat was strengthened. It was still shapeless to us, but it was more real.

As David goes on to comment, this decision they make together was what began their collective consciousness as a group - "it made us into a group." From this point on, the group thinks and acts as a group, working together (except of course when one of them chooses to marry outside of the group).

The discovery of Sophie and her fleeing and capture, combined with the suicide of David's Aunt Harriet and presumably the death of her baby in Chapter 7 equally serves to reveal to David what is at stake if their "gift" becomes known. As he comments, "And I went on being very frightened." David even prays to be "normal".

When Anne chooses to marry outside of the group and in Chapter 10 is found hung after the death of her husband, it is clear that this fear they have of discovery is heightened. It was just by chance that Rachel managed to obtain Anne's note of confession and thus saved the group from discovery. The group live in a dangerous world where at any moment they could be found out with horrifying consequences, as displayed by Sophie and Aunt Harriet. These really are the key events that form David Storm and prepare us for the group's discovery of Petra, which of course equally destroys the group and gives some of them hope for the future.

At the beginning of the story, David is young, about ten years old.  As a youngster, he is kind and considerate.  When he meets a little girl who gets her foot stuck, he helps her instead of turning her in because she has an extra toe.

David is surprised when Sophie’s mother thanks him and tells him he’s a good boy.  He is not sure how to respond.

I felt awkward, and looked at my shoes. I couldn't remember anyone saying before that I was a good boy. I knew no form of response designed to meet such an event. (ch 1)

David’s upbringing was sparse.  His father was stern and his mother not much better.

Despite being young and having an over-bearing, tyrannically religious father, David still manages to have a mostly peaceful childhood.  His biggest problem is that he has a special power that makes him different.  David is telepathic in a community where deviance is not accepted.

One of the first milestones for David growing up, when he has to become more mature, is when he realizes that his little sister Petra is telepathic too.  Since she is too little to control her emotions, he has to protect her.

At the beginning of John Wyndham's The Chrysalids, I would suggest that one of David's most outstanding characteristics is his innocence and the trusting nature that comes with it.

His innocence is easy to see at the start of the story. When David meets Sophie, and accident while playing exposes her foot with six toes. David thinks nothing of it, though Sophie is greatly distressed that he has seen it, and Sophie's mom is also extremely upset, telling David Sophie will suffer if it is discovered, and begging him for his oath never to tell anyone what he has seen.

"It's very, very important," she insisted. "How can I explain to you?...If anyone were to find out they'd—they'd be terribly unkind to her."

David quickly promises to remain silent. At first, however, he cannot understand how having six toes could be such a big deal:

It was so heavy a promise that I was quite resolved to keep it...Though, underneath, I was puzzled by its evident importance. It seemed a very small toe to cause such a degree of anxiety.

David is still very uninformed. On his way home, he tries to understand. Why would Sophie and her mother be so fearful? In a moment of insight, things fall into place. David can begin to understand what society expects:

Then [the monotonous Sunday precepts join up] with a click that was almost audible..."and each leg shall be jointed twice and have one foot, and each foot five toes, and each toe shall end with a flat nail...And any creature that shall seem to be human, but is not formed thus is not human...It is a blasphemy against the true Image of God, and hateful in the sight of God."

One incident that foreshadows trouble is when Alan sees the imprint of Sophie's wet foot on the rock that she has just left. Alan is much too interested to simply be curious, and David feels a tangible threat:

I looked up and saw that [Alan] was staring at something beside me. I turned quickly. On the flat rock was a footprint, still undried...The mark was still damp enough to show the print of all [Sophie's] six toes clearly. I kicked over the jar...but I knew...that the harm had been done...he had turned and was standing looking along the bank towards the point where Sophie had disappeared into the bushes.

I ran up the stone and flung myself on him.

When David returns home, the news reaches his father that he has consorted with a mutant and kept her secret. To get information, David's father beats him badly. Perhaps it is his father's fury that finally opens his eyes to the dangers of the society in which he lives—something he had never understood before. Betraying his promise to Sophie is devastating.

By now it was not so much the bodily hurts that brought [tears]: it was bitterness, self-contempt, and abasement...'I couldn't help it, Sophie,' I sobbed.

What finalizes any doubts David might have is his Uncle Axel's explanation that he is in danger. David's telepathic abilities make him a mutant, and therefore, a threat. His uncle warns him:

I want you to keep it a secret. I want you to promise that you will never, never, tell anyone else what you have just told me—never. It's very important: later on you'll understand better how important it is. You mustn't do anything that would even let anyone guess about it. Will you promise me that?

David is a young man living in a society he does not understand. His father's ferocity, Sophie's capture, and his own abilities change the way he sees the world forever.

At the start  of John Wyndham's novel, The Chrysalids, David (the main character) is young and innocent. He is unaware of the deep significance of what takes place around him with regard to his culture's wish to wipe out the "mutants."

When David realizes that Sophie has an extra toe, he is not quite sure what all the fuss is about—particularly that he is sworn to secrecy.

It was so heavy a promise that I was quite resolved to keep it...Though, underneath, I was puzzled by its evident importance. It seemed a very small toe to cause such a degree of anxiety.

On his way home, some part of the society's teachings about "mutants" becomes clear, but still does not form a deep enough impression on David. The Sunday "precepts" connect...

...with a click that was almost audible...The Definition of Man recited itself in my head: '...each leg shall be jointed twice and have one foot, and each foot five toes, and each toe shall end with a flat nail...'

This small realization still does not quite impact the boy. David returns home and sees the same signs on the walls in his home that have always been there—but he has really never understood the context of these statements or how they impact others.

The nearest approach to decoration was a number of wooden panels with sayings, mostly from Repentances, artificially burnt into them. The one on the left of the fireplace read: ONLY THE IMAGE OF GOD IS MAN...KEEP PURE THE STOCK OF THE LORD...WATCH THOU FOR THE MUTANT!...Many of them were still obscure to me.

We see a distinct change in David when he is beaten for having knowledge of Sophie's condition and not reporting it. After his father is done with him, while his sister Mary dresses his wounds, David reflects on what has happened:

By now it was not so much the bodily hurts that brought [tears]: it was bitterness, self-contempt, and abasement...'I couldn't help it, Sophie,' I sobbed.

In being beaten, David told what he knew about Sophie and feels guilty—self-contempt; but the bitterness he experiences speaks to anger and resentment, against the world that has such laws, and a father who seemed not to hesitate in delivering his "torture" to force his knowledge from him, along with his punishment as well.

We now see a new David. He shares (telepathically) with his friends that what they have been taught is wrong—that Sophie was not a threat. The others struggle with this news, however...

You can't lie when you talk with your thoughts. [The others] wrestled with the novel idea...

Now David knows more of the world and he has passed his own judgment: his family and his society are wrong. David becomes an independent thinker.

The reader comprehends to what extent David has grown as the telepaths realize that they have been discovered. Alan knows everything his wife (Anne—a telepath) told him before she killed herself, and others are suspected. Michael tells David he must be prepared to kill if necessary to save them, and he must be especially responsible for Petra, as she is the weakest of them.

If worst comes to worst, and you can't save Petra, it would be kinder to kill her than let her go to sterilization and banishment to the Fringes—a lot more merciful for a child.

David understands and agrees. The next day he is called to act—they must flee. His strength of character allows the more mature David to lead his group away from civilization: escaping the Fringe people and finally finding safety with the Sealand people.

David's fear continually increases through the progress of The Chrysalids on account of different occurrences at points in his life. One such occurrence are the two incidents involving Sophie. First, her foot gets caught and to release it, David removes her shoe, noticing that she has six toes. Afterward, Sophie's mother interrogates him and then begs him to keep their secret: Sophie is a Deviant and a Blasphemy according to Waknuk law.

Then one day when he and Sophie are playing in a creek, he ill-advisedly encourages Sophie to go barefoot and Allan comes along and sees Sophie's footprint. Sophie and her family flee, but are caught. Sophie is punished and banished.

These incidents cause David to realize the import of the Definition of Man: "...on each foot, five toes...." The Definition declares that any Deviation is not human though it may seem to be human. David has nightmares and realizes that death can could come to a Deviant he knows and recognizes to be human, despite the definition. These thoughts all begin to apply to himself, as well, as his deviant telepathy becomes a greater part of his life.

Another such incident revolved around his Aunt Harriet's death. She had given birth to a baby girl who was a Deviant. She had turned to her sister, David's mother, for help. All she received was reproach and accusations of evil from David's mother and father. It was then that David turned to praying earnestly that his deviation be removed from him. These incidents and others all contributed to David's growing fear, especially as Petra kept getting into trouble and exposing the telepaths by her screams of terror.

David is sensitive and intelligent, and he has the ability to read minds.

David can’t read just anyone’s mind, but he is part of a special group of individuals who are telepathic.  They can communicate with each other through their minds over distances.  This is very dangerous in David’s society, where great importance is placed on everyone being perfect and matching the “true image.”

Despite the fact that David has been raised with a strictly religious father, he is a kind soul.  When he meets a little girl one day who has injured her foot, he helps her even after he realizes she has extra toes.  Such a thing is condemned by his society.  She would be considered a mutant. 

The commandments and precepts one learns as a child can be remembered by rote, but they mean little until there is example  … Thus, I was able to sit patiently and watch the hurt foot being washed, cold-poulticed, and bound up, and perceive no connexion between it and the affirmation which I had heard almost every Sunday of my life. (Ch. 1) 

He continues his friendship with Sophie, protecting her even after they are seen.  His father has to beat the secret out of him, and then he feels terrible for betraying her.  Despite being young, David instinctively understands that demonizing people because they are a little different is wrong. 

The love of David’s life is Rosalind.  He says that he has loved her for as long as he can remember.  Due to a family feud, their relationship is forbidden.  Outside of the group of telepaths, their relationship is not widely known. 

We used to meet, discreetly and not dangerously often. No one but the others, I think, ever suspected anything between us. We had to make love in a snatched, unhappy way when we did meet, wondering miserably whether there would ever be a time when we should not have to hide ourselves. (Ch. 10) 

Eventually their secret is revealed, and all of the telepaths have to go on the run.  David’s past and present seem to collide, but he still does his best to be kind to Sophie even though he loves Rosalind when he sees her in the Fringes.  David and Rosalind are able to escape with the Sealanders.