Nate's grandparents take the Wrights on an ill-fated seafaring adventure to find the rumoured lost treasure of Eewcorpico; Captain Dee Dee leads a rescue mission to save Nate and his family from the treasure's curse.

Nate and Teddy go to great lengths to get invited to hang with the cool 7th graders, but they get more than they bargained for when they find out just how much more intense middle school gets after 6th grade.