Ladybird 
Ladybird Readers Level 4 – The Wizard of Oz (ELT Graded Reader) 

One day, a storm took Dorothy and Toto to the Land of Oz. Dorothy liked the new friends she met, but she wanted to go home.
Ladybird Readers is a graded reading series of traditional tales, popular characters, modern stories, and non-fiction, written for young learners of English as a foreign or second language.
Beautifully illustrated and carefully written, the series combines the best of Ladybird content with the structured language progression that will help children develop their reading, writing, speaking, listening and critical thinking skills.
The eight levels of Readers and Activity Books follow the CEFR framework and include language activities that provide preparation for the Cambridge English: Young Learners (YLE) exams.
The Wizard of Oz, a Level 4 Reader, is A2 in the CEFR framework and supports YLE Flyers exams. The longer text is made up of sentences with up to three clauses, more complex past and future tense structures, modal verbs and a wider variety of conjunctions.