One September evening in 1785, one of Jonah Hancock's captains arrives - having sold Jonah's ship for what appears to be a mermaid. As gossip spreads through the docks, coffee shops, parlours and brothels, this marvel spins him out of his ordinary existence and through the doors of high society. A spell-binding story of curiosity and obsession set in 18th century London. For fans of "The Miniaturist" and "The Essex Serpent".