Abandoned by her father years before, 12-year-old Lou has built a hard, angry shell around her heart. She lives with her single mum Rhia and two sisters in a run-down rented house. The only bright spot is Blake, the goofy teenager up the road.
Into this house of girls comes a man – Doyle – Lou’s paternal grandfather, a tough-talking former merchant sailor. Lou wants Doyle out – he just reminds her of the father she doesn’t have – but Rhia refuses, wanting to keep her carer’s allowance.
Doyle brings chaos to the household. He’s constantly trying to escape, looking for his former wife, Annie – the woman who broke his heart when she ran off with another sailor, Fred Fletcher.
Then something strange and wonderful happens. Doyle confuses Lou with Annie. He begins to court her and Lou plays along, using it in her power struggles with her mother.
Through the game playing, however, Lou discovers that she does care. Her heart even begins to soften towards her mother.
When Doyle, deep in his fantasy, proposes to Lou, she accepts his offer of love. Although she’s playing with fire, Lou starts to feel beloved for the first time.
Rhia discovers the “engagement” and forces Lou to stop the game. Without his anchor, Doyle becomes even more disoriented – attacking Blake when he thinks he’s trying to steal Lou/Annie away. Rhia organises for Doyle to go and Lou turns on her mother, decrying her lack of love.
Lou, afraid of losing Doyle, runs away with him but is forced to recognise that he needs more care than she can give him. She returns home with him, and he is taken away.
Lou, feeling the grief, reaches out to her mother, who welcomes her into her arms.
Some time later, Lou and her family revisit the beach. They see a ship sailing past and Lou, with Doyle still in her heart, waves goodbye.