Anne is given a diary for her 13th birthday. Anne's parents decide to go into hiding from the Nazi's after call up papers arrive for her sister.

Otto finds out that the building everyone is hiding in has been sold. Everyone hopes that the war will be over in a few months as the lease to the building wont be exchanged until then. Mr Dussell misses his fiance.

As Anne matures she begins to develop feelings towards Peter and flirts with him. After Otto tells her not to get too involved, Anne and Peter end up declaring their love to each other.

When Anne's family found out the Dutch government want diaries telling of war time experiences Anne is encouraged to submit hers. Determined to be a professional writer, Anne finds herself with no time to spend with Peter. As Anne is writing an entry into her diary, she and her family are suddenly awakened by the sound of intruders downstairs.