Amy and Dan Cahill face their greatest challenge on their quest to find the thirty-nine clues, but in order to discover the secrets of their lineage they will have to make a choice that could impact the world's future.

"Are some secrets better left buried? As Amy and Dan track the next clue to a remote corner of the world, they make shocking discoveries about the source of the Cahills' power and the mystery of their parents' deaths. And as the threat of the mysterious Madrigals grows real, one of the clue-hunters makes the ultimate sacrifice. Amy and Dan have to decide how much they're willing to risk, and what they are fighting for. Can they avenge their parents...

Amy and Dan are hot on the trail of the fourth Clue, but their ruthless relatives will stop at nothing to eliminate them from the competition. Their hunt leads them to an ancient city that has been a hotbed of Cahill activity for centuries. The clock is ticking for Amy and Dan.

"A family mystery leads Dani Beans to investigate the secrets of Ole Miss and the dark history of race relations in Oxford, Mississippi"--

Told in two voices, Jaya Rao, an East Indian princess, and Grey Emerson, an English lord, suffer the effects of a centuries-old feud when they meet at an elite Colorado boarding school.

When he accidentally trips over a grave Stan Summer lands in the middle of a century-old feud between two rival ghost families, and finds himself cast in the role of peacemaker.

While celebrating the New Year with a friend, Sammy encounters a mystery involving an elderly neighbor, a pioneer cabin, and a century-old family feud.

In the 1880s, young Fanny McCoy witnesses the growth of a terrible and violent feud between her Kentucky family and the West Virginia Hatfields, complicated by her older sister Roseanna's romance with a Hatfield.

A prose retelling, incorporating lines from the play, of the tragic consequences of a deadly feud between two rival families in Renaissance Verona.