English Tree was a series for young teens in Greece, and I got to write the Student's Book for one of the levels. A storyline ran through the book, and each unit opened with an instalment of the story. Pushing the story on, and including useful vocabulary, and including target grammar, and making it all engaging was very tricky, but very satisfying. I'm very proud of the time-travelling tale of Ben, Martha, Doc and Catastrophe the Cat in their adventures against the Professor and his side-kick, Test-tube!