In the fourth of Katie's Glowstone Adventures, she is transported to the South Pacific to help a green turtle and his best friend, a crown-of-thorns starfish, both with very sore tummies caused by eating bits of plastic floating in their ocean. Their beach has also become littered with plastic rubbish and they keep getting tangled up in it. Katie needs to help two creatures this time, clean up a beach and an ocean! Is this adventure a step too far for Katie and her trusty Glowstone?