By all accounts, Sally Townsend of Oyster Bay was a very attractive young lady - petite, vivacious, intelligent and remarkably beautiful. But her large beguiling eyes were her most striking characteristic, referenced in a 1779 Valentine poem from an admiring British officer: ""Thou know'st what powerful magick lies Within the round of Sarah's eyes."" She was the sister of Robert Townsend, a principle member of the ""Culper Ring,"" General Washington's most effective spy network. During the British occupation (1776-1783), Redcoat, Hessian and Loyalist officers were quartered in the Townsend home, and Sally assisted her brother in gathering intelligence, coyly flirting with the enemy. She was the romantic interest of Jager officer Ernst Wintzingerode, dallied with Major John Andre, the British adjutant general, and was courted by Lieutenant Colonel John Graves Simcoe of the Queen's Rangers. This book tells the story of Sally Townsend, her secret service during the Revolutionary War and the heavy price she paid for her role in thwarting the Benedict Arnold treason plot. The author explores the possible identity of the mysterious ""Agent 355"" mentioned in a cryptic Culper Ring message.