Three young friends are transported by a magic seashell to solve an environmental mystery: sea otter pups are being abandoned by their mothers outside of the aquarium, and no one knows why!

Riley, a shy third grader, puts her skills as an artist to the test when she becomes the lead detective on the case, drawing every clue she sees in her favorite nature journal.

Can Riley, along with her sister and best friend, gather the right clues to figure out who is behind it all before more otters are in danger?