Set in 1961, the novel follows an eccentric community of houseboat owners whose permanently moored craft cluster together along the insalubrious bank of the
River Thames at Battersea Reach,
London. Nenna, living aboard
Grace with her two children Martha and Tilda, is obsessed with thoughts of her estranged husband Edward returning to her, while her children run wild on the muddy foreshore. Maurice, who lives next to her on a barge he has named
Maurice, provides a sympathetic ear for her worries. He ekes out a precarious living as a male prostitute, bringing back men most evenings from the nearby pub, and allowing his boat to be used for the storage of stolen goods by his shadowy acquaintance, Harry. Willis, an elderly marine painter, lives aboard
Dreadnought which he hopes to sell in spite of its serious leak. Woodie is a retired businessman living aboard
Rochester during the summer and with his wife Janet in
Purley during the winter. Richard, aboard his converted
minesweeper Lord Jim, is looked up to as the unofficial leader of the community, both by temperament and by virtue of his past role with the
Royal Naval Volunteer Reserve. His wife Laura hankers to move to a permanent house ashore. When
Dreadnought unexpectedly sinks, Willis is taken in by Woodie on
Rochester. Nenna resists the entreaties of her prosperous and energetic sister, who tries to persuade her to move to Canada for the sake of her daughters, and she resolves to confront Edward in his rented room in
Stoke Newington, north London. Failing to persuade him to return, she gets back to
Grace late at night feeling desolate, and bumps into Richard who tells her that his wife has just left him. They spend the night together. Richard discovers Harry acting suspiciously on
Maurice. Harry attacks him, and Richard ends up in hospital. Laura takes her husband's incapacity as the excuse she needs to sell
Lord Jim and to move herself and Richard into a proper house. Maurice sits out an overnight storm in his cabin, drinking whisky in the dark. He hears blundering footsteps overhead and discovers that Edward (whom he does not know) has returned, incapably drunk, trying to find Nenna. The storm has blown away the gangplank between
Maurice and
Grace and, almost delirious with drink, the two men climb down
Maurices fixed ladder, intending somehow to cross the wild water between the two boats. As they cling to the ladder,
Maurices anchor is wrenched from the mud, its mooring ropes part, and the boat puts out on the tide. ==Principal characters==