On her thirteenth birthday, Anne Frank’s parents give her a diary. She’s excited because she wants someone—or something—in which to confide all of her secret thoughts. Even though she has a rich social life, she feels misunderstood by everyone she knows. Anne starts writing about daily events, her thoughts, school grades, boys, all that.
But, within a month, her entire life changes.
As Jews in German-occupied Holland, the Frank family fears for their lives. When Anne’s sister, Margot, is called to appear before the authorities—which would almost surely mean she was being sent to a concentration camp—Anne and her family go into hiding. They move into a little section of Anne's father's office building that is walled off and hidden behind a swinging bookcase. The little diagram of the office building and "Secret Annex" in the Thursday, July 9, 1942 entry gives us the layout.
For two years, the Frank family lives in this Secret Annex. Mr. and Mrs. van Daan and their son Peter (who is a few years older than Anne) are also in hiding with the Franks. Later, Mr. Dussel (an elderly dentist) moves in, and Anne has to share her bedroom with him. Anne’s adolescence is spent hidden from the outside world. She’s cooped up in tiny rooms, tiptoeing around during the day and becoming shell-shocked from the sounds of bombs and gunfire at night.
Luckily, the Franks have tons of reading material and a radio. Anne grows in her knowledge of politics and literature, and she puts tons of energy into studying and writing. At the same time, she grows further and further away from the other members of the Annex.
We see a real change in Anne when she begins hanging out in the attic with Peter van Daan. Around this time she starts having dreams about a boy she was in love with, another Peter: Peter Schiff. She sometimes even gets the two Peters confused in her head.
She comes to see Peter (of the Annex) as much more than she first thought. She finds him sensitive and caring, and they talk about everything, including sex. Eventually their relationship changes. Anne and Peter’s passion turns into a friendship and a source of comfort for them both.
Another big change for Anne happens when the war seems to be ending. She hears that personal accounts such as her diary will be in demand after the war ends. We see a return to her earlier optimism as she begins editing her diary with vigor and excitement.
Unfortunately, this does not last. Even as Anne becomes more and more sensitive to the suffering going on in the world, her own suffering becomes unbearable. She feels completely alone. She thinks everyone hates her. She feels constantly criticized. And there is no escape. At one point, she thinks it might have been better if she and her family had all died instead of hiding in the Annex. As Anne becomes harder on those around her, she also becomes harder on herself, berating herself for being mean to the other members of the Annex.
There her diary ends. Two short months after Anne’s fifteenth birthday, and two days after he last diary entry, the Secret Annex is raided. We don’t know Anne’s thoughts or feelings at that point or any time after, but we know things got worse.
As you probably already know, Anne and the other members of the Annex were sent to various concentration camps. Anne's father, Otto Frank, was the sole survivor.