A duel at dawn. One man dead, the other gravely injured. What drove them to fight on a bitterly cold morning remains a mystery.

For years, Lady Bancroft’s Valentine’s Ball at Bancroft Hall had been a glittering gathering of high society’s most eligible men and women. Countless happy couples owe their love stories to her matchmaking, their gratitude keeping Lady Bancroft in the genteel comfort of her grand Cotswolds estate.

But this year tragedy strikes. A murder threatens to ruin everything.

Desperate, Lady Bancroft turns to her neighbour, the dashing Major Heathcliff Lennox. A decorated war hero and now a consultant to Scotland Yard, Lennox would much rather be fishing. But duty—and the insistent ex-detective Inspector Swift—calls.

What seems like a straightforward case takes a darker turn when another body is discovered. With secrets unraveling and suspects mounting, Lennox and Swift must race to uncover the truth before the killer strikes again.

Meanwhile, Lennox's wife, Persi, an archeologist, is handed a mystery of her own. The Valentine's Murder is not the only mystery at Bancroft Hall, there was the centuries old mystery of the lost Lady of Lisle.

In 1415 Sir Edward Parcival Bancroft joined King Henry the fifth's retinue to wage war in France. Edward distinguished himself at Agincourt and was ennobled for his bravery and valour.

King Henry returned in triumph to London. Lord Edward Bancroft rode south, exploring a country he'd become enchanted with. He reached Lisle, and fell in love with the daughter of the local Seignour, Lady Madeleine de Lisle. They married and he escorted her home to Bancroft Hall. For six months they appeared happy and content. Then one fine summer's day, Lady Madeleine walked out of the house and vanished, never to be seen or heard of again.

Unless Persi, and Swift's wife, Florence can find her, or at least, uncover what happened to her...