The mansion of larger-than-life business magnate Titus McAvoy hums with the energy of his servants Nessa and Aoife, two Irish maids bonded through their journey to America, and a dream of escape. When preparation for one of Titus's famous parties sends the pair to the beach, Aoife stumbles upon a strange find on the shoreline. She instinctively pockets it, unaware that it is the key to her and Nessa's freedom. Ambergris holds more worth than silver or gold.

Amid this discovery, a young white-passing British World War I veteran named John enters the mansion's ranks, his history dragging behind him. When John's path intersects with Nessa and Aoife, the trio forms a quiet trust. Eventually, the girls show John the ambergris treasure, and together, they formulate a plan to cash in their secret and make their getaway.

These three friends are determined to forge a different life together—one free from how the rich treat the poor, and free from the pervasive rot of nationalist and racist behavior, not to mention the injustices and dangers that too often befall women. But with a crash in the stock market demolishing Titus's wealth, his eye is sharp and malicious. As the trio's strategy unfolds, so too does their boss's own merciless plan to punish whoever defies his power. Nobody walks away from Titus McAvoy.