On 17 April 1685, the merchant ship Mytilida leaves on a transatlantic voyage with enslaved people, child sailors and one all-seeing mussel on board. This remarkable mollusc keeps a log, recording everything that goes on above decks and below, yet it knows nothing about slavery. This raw, poetic and visually powerful book provides a fresh, subversive view of slavery, gives full scope to voices that history has often left unheard, and creates a lasting impression.