Alien Alert in Seattle (level 1)

There has been a UFO sighting in the Cascade mountains near Seattle, Washington, and everyone is excited. But no one believes there could possibly be an alien in town, until Karen, Barbara and Walter notice that one of the teachers at their high school is behaving very strangely. Karen and her friends start investigating on their own and are very surprised by what they discover... 

Dossiers:
Introduction to Seattle, The solar system, UFOs, American teenagers and High School