Croeswch drosodd i fyd sy’n llawn llên gwerin hynafol gydag awdur arobryn Bearmouth. Mae gwyliau gaeaf ger yr arfordir i fod yn drêt i Kit, ei chwaer Libby a’u mam. Ond wrth i’r lleuad godi’n uchel yn yr awyr, mae Kit a Libby’n cael eu denu at dŵr gwyn dirgel, dim ond i wynebu trychineb pan fydd Libby’n diflannu. Mae’r byd wedi ailysgrifennu ei hun, gan adael i Kit lywio realiti lle nad yw ei chwaer erioed wedi bodoli. Ond wedyn, mae Kit yn cwrdd â Story, bachgen lleol sy’n cofio Libby yn berffaith. Gyda’i gilydd, maen nhw’n cychwyn ar daith beryglus – ydyn nhw’n gallu achub Libby cyn i amser ei hun ddiflannu?
Cross over into a world steeped in ancient folklore with the multi-award-winning author of Bearmouth. A winter holiday by the coast is supposed to be a treat for Kit, her sister Libby and their mum. But as the solstice moon rises high in the sky, Kit and Libby are drawn to a mysterious white tower, only to face disaster when Libby vanishes. The world has rewritten itself, leaving Kit to navigate a reality where her sister has never existed. But then Kit meets Story, a local boy who remembers Libby perfectly. Together they embark on a perilous journey – can they rescue Libby before time itself vanishes?
