Checking their bird book , they believe that these are great northern divers .
The story is set in the Outer Hebrides , where the main characters -- a group of children on holiday -- notice a pair of divers apparently nesting there .
Checking characters ' bird book , characters believe that these are great characters divers .
The story is set in the Outer Hebrides , where the main characters -- a group of children on holiday -- notice a pair of divers apparently nesting there .