Jessie wants her science fair project to make a difference. So when she gets the chance to test a local creek for pollution, she can't wait to get started. But when things start going wrong with her experiment, Jessie and her siblings don't just have an experiment to investigate, they have a mystery to solve!

Obe Devlin spends a lot of his time cleaning up the creek that runs through what little is left of his family's once extensive farmland, and worrying about what the developers are doing nearby, and the pollution it is causing--but one day he finds a strange creature by his creek that eats plastic, and soon the animal he calls Marvin Gardens becomes his personal secret, which he believes needs to be protected from pretty much everybody.

Alba the fish has spent her entire life collecting precious objects that drift down to the ocean floor. From delicate shells to brightly colored coral, each year on her birthday she gathers one more precious item. But over the years, Alba notices her collection is losing its sparkle and that the world is changing. There is trash everywhere! When, on her birthday hunt, something unthinkable happens, it seems like the plastic may have changed her ocean...