Strange things happen in the grove of the children of the tree house. Someone pours out piles of building debris at night in the heart of nature, and in the wooden house a sleeping bag and a strange suitcase are discovered. Is there a connection between the two things? The children of the tree house are determined to solve the mystery themselves, despite the danger, because when they have a good goal, they sometimes don't give up. The children's project of Yaya's tree house (the snake fish) and Ran Cohen Aharonov has in a short time become a unique phenomenon in the Israeli culture for children. The books in the series - From a grove, to free an infidel and an unusual child - were very popular and were selected for the Ministry of Education's book parade; The show, the musical albums and the show with the best musicians in the country were praised; And the television series won the Academy Awards for television. The Children of the Tree House - Knights of the Green Table, the fourth book in the series, is also accompanied by the illustrations of Yaniv Shimoni, one of the leading illustrators in Israel.