Check for consistency in the plot. If the lighthouse device emits a pulse, maybe the map reacts to that pulse in another location. Or perhaps activating the device too many times causes depletion or other issues. The consequences of their actions should matter.

Now, moving into Chapter 11, the story should continue from where they are in Oregon. The main characters are the Jenkins family: Mr. Jenkins, his daughter Emma, son Daniel, and their dog Max. There's also Ben, the local guide, and the mysterious elements like the shadow creatures and ancient artifacts.

I should start by outlining the chapter. Maybe they use the map to find another location, perhaps a mountain or cave that's marked. They encounter another ancient site where they find another artifact or puzzle. The shadow creatures return, escalating the danger. The family has to work together to use the new artifact, which might involve solving a riddle or overcoming a trap. This could lead to a revelation about the purpose of the artifacts or the threat posed by the shadow creatures.