Hannah adores her Grandad. The trouble is, Grandad has Alzheimer's and he's always forgetting things. He keeps trying to tell Hannah a story about a whale, and it seems really important, but it's all jumbled up. Then Grandad has a stroke and he can't remember anything, not even Hannah. It's like he's lost inside himself. Determined to get Grandad back, Hannah sets out to make a film that will remind him of his life - and in so doing, starts to piece together an extraordinary story about a whale that connects Grandad's childhood to her own.