The Black Widow and Red Widow have inherited something from their shared past--a need for vengeance adgainst deceased Ivan Somodorov's network of terror.

Growing up in 1943 war-torn England, thirteen-year-old Alice and her older sister Louise are members of a centuries-old spy clan, but when Louise decides to spy for the enemy, their bond is changed forever.

"When Queen Joanna is kidnapped Charlie and Violet set out across South America to find her and discover a conspiracy to raise the dead"--

When the evil Galina Krause suddenly reappears, the Kaplan family must race to find an artifact believed to be crafted by Leonardo da Vinci in their quest to uncover Galina's endgame.

As Wade, Darrell, Lily, and Becca continue their search for an ancient relic, Wade's mother is kidnapped by Galina Krause, leader of the present-day Teutonic Knights.

Natasha Romanov, called the Black Widow, agent of S.H.I.E.L.D, rescues a young girl from Ivan, the man who once trained her as an assassin--and eight years later she is called upon to protect the teenage Ava from a threat from the past--and possibly from S.H.I.E.L.D itself.

When Michael Malone saves a dog, he discovers that he has paranormal abilities, which bring him to the attention of a secret organization, UNICORNE--but he plans to use the ability to find out what happened to his father, who mysteriously vanished three years earlier, and save his new friend, Freya.

When a suspicious death coincides with the discovery of fossilized dinosaur bones, Kat knows this case is for her, if she can juggle everything happening in her life, including clues she has uncovered about a secret society.

Sam (a puzzle master) and Martina (a history whiz) become involved in a dangerous quest to find seven keys left behind by Benjamin Franklin and a secret society of descendants, which, when gathered together, unlock a powerful weapon, so the middle schoolers must solve the puzzles, find the artifacts before the bad guy does, and save the nation.

"A strange telegram lures fourteen-year-old Amy Cahill and her younger brother, Dan, deep into Russia and away from the only trustworthy adult they know. Signed with the initials NRR, the telegram launches a race to uncover a treasure stolen by the Nazis and the truth behind the murder of the last Russian royal family. All too soon, the treasure hunt starts to smell like a Lucian trap. But the bait might just be irresistible--what will Amy and Dan...