The second fantastic book in the series about four friends who want to make the world a better place. Izzy and Poppy are being taking their boisterous dog, Billy, for a walk when he lands in the river. It is so choked with rubbish that Billy can't get out. A brilliant series about the small changes that make a big difference, with themes of environmentalism and friendship.

Mae'r pethau bychain yn gallu gwneud gwahaniaeth MAWR! Mae Ffion yn cael sioc o weld yr holl sbwriel a llanast sy'n llenwi'r afon leol. Pan mae ci ei ffrind bron â boddi oherwydd hen feic rhydlyd, mae hi'n benderfynol o newid pethau er gwell. Ond sut y gall un person berswadio cymuned gyfan i achub yr afon?