The Mystery of the Alien Invaders
The clues: A plastic snake, damaged tree bark, and a picture of a lamprey mouth The file label: "Who invited aliens?" E.B. wonders if the mystery could be about outer-space aliens (the lamprey sure looks like one!). But when Kyla helps capture a huge escaped python and examines a real lamprey while E.B. examines a beetle-infested tree, they realize the mystery is about invasive species. The snake, the lamprey, and the insects that damaged the tree bark were all accidentally introduced by human travel and trade. Turns out, we invited aliens!