This time, it's an adventure on the wide-open ocean, and everyone's favorite girl detective, Ruby Redfort, is out at sea. Can she crack the case of the Twinford pirates while evading the clutches of a vile sea monster as well as the evil Count von Viscount? Well, you wouldn't want to bet against her!

Mr. Summerling, Marly's neighbor, talked about being a treasure hunter, and news of his death has brought Marly into a treasure hunt of her own. In his will, Mr. Summerling left a treasure for Marly and two classmates, Isla and Sai. They barely know each other, but they have to work together with a series of riddles, puzzles, and clues to find the treasure.

Wild animals roaming around Twinford? Wisecracking Ruby Redfort has heard the rumours, though she doesn't quite believe them. But as high society buzzes with news of a very exclusive perfume formula coming to town and some priceless jewellery goes missing, Ruby begins to sense a sinister plot in the works. Can our favourite action hero sniff out the clues in time to keep Twinford safe from evil scents? Well, let's just say this is one of those times...

On an island nation in the Indian Ocean, the explorers venture through a vast underwater world and take part in a friendly robotics competition. But the tides of good fortune change quickly. Suddenly, Team Cousteau jumps into action to rescue a faculty member from the brink of death. Meanwhile, the team follows the Cruz's mother's clues to a magnificent tomb and center of spirituality precariously perched on the side of a cliff. There, Cruz is confronted...

Told in multiple voices, fifteen-year-old Jamaican Louisa Adair uncovers an Enigma machine in the small Scottish village where she cares for an elderly German woman, and helps solve a puzzle that could turn the tide of World War II.

It was only a few days ago that Tess Biedermann, Theo Biedermann, and Jaime Cruz, along with a mysterious figure from the past, managed to survive an assault on the location of the latest clue in the Morningstarr cipher -- and, in the process, made a shocking discovery about their own connection to this one-hundred-sixty-year-old enigma. Now the friends are divided. Tess and Theo have no idea what the photo they found in Greenwood Cemetery means,...

A cryptic message forces eighteen-year-old American Edda to investigate what secrets followed her across the ocean, even as she tries to make sense of her time as a telephone operator on the French front lines of World War I.