Late in 1918, the "Iolaire," a Royal Navy yacht carrying several hundred soldiers home to the Scottish islands of Lewis and Harris, sank in a storm off Stornoway Harbor. Over 240 were drowned, a crushing blow to an island community that had already lost 800 men in the Great War. The "Iolaire" tragedy served as the stimulus for this fictional account of friendship and love in the Hebrides islands during the War of 1914-1918.

At the book's center are three characters who form an emotional and spiritual triangle: Iain, a young poet who survives the European battlefields only to die by drowning in the "Iolaire" on his way home; the beautiful and vivacious Mairi, pregnant with Iain's child, but in reality in love with Callum; and Callum, a small town newspaperman whose disability keeps him out of the army, and who falls head-over-heels in love with Mairi.

Mairi leaves the island and travels to England to have her baby, planting the seeds of a future that we learn about in stages as The Dark Ship moves back and forth in time from 1916 to 1939 to 1996, and the fates of the characters are gradually revealed. In particular, we learn that after his death Iain Murray became world renowned as a soldier poet. Iain, whose friends never knew that he was a writer, left at his death a manuscript of poems, which his friend Callum Morrison arranged to have published in 1919. On the basis of that book, in MacLeod's fictional world Murray has come to rival such great first world war poets as Siegfried Sassoon and Wilfred Owen. (Murray's famous collection, called "A Private View," is appended to the novel.)