The Hoodunnits have another mystery to solve. The rare nutjar seed has been stolen from the botanic gardens. Will they find the thief and get the seed back? Family Tree is Oxford Reading Level 11. It is for readers aged 7 to 11 years old who are working below expected standard in their reading. The Readerful Rise series ensures that older struggling readers have books with age-appropriate content and topics, that look like the books their peers are enjoying, but are written at a level they can read successfully.